Thanks to Picaroon. An enjoyable puzzle, even if I had to think hard for the last couple in. Definitions are underlined in the clues.
Across
1 School teashop recycling waste here (7,4)
COMPOST HEAP : COMP(short for a “comprehensive school”, a type of secondary school in the UK) + anagram of(… recycling) TEASHOP.
9 Country crime waves interrupting drivers (7)
AMERICA : Anagram of(… waves) CRIME contained in(interrupting) AA(abbrev. for the Automobile Association, an organisation whose members are vehicle drivers).
10 Tanks in army’s front, as bearing westwards (7)
AQUARIA : 1st letter of(…’s front) “army” + QUA(as/by virtue of being, as in “the prime minister qua head of his party led the debate” + reversal of(… westwards, in an across clue) AIR(bearing/demeanour that conveys some personal quality or emotion).
Defn: … for keeping live fish and other water creatures and plants.
11 Between 9 and 11 put on clothing that’s playful (9)
KITTENISH : TEN-ISH(approximately between 9 and 11, as in “let’s meet between 9 and 11 am, say, 10-ish”) placed after(put on) KIT(clothing/gear you’re wearing).
12 How Brexit begins with hopeless nationalist (5)
BLIMP : 1st letter of(How … begins) “Brexit” plus(with) LIMP(hopeless/useless).
Answer: Colonel Blimp, a cartoon character who was jingoistic and stereotypically British, whom you might call a nationalist, right or wrong.
I liked the undertones of the clue’s surface.

13 Unacceptable to lose heart in retreat (4)
NOOK : “not ok”(unacceptable) minus its middle letter(to lose heart).
14 Note covering wraps round nuts and washer (10)
LAUNDROMAT : [ LA(note in the musical scale) + MAT(a covering/a rug/a piece of material placed over part of a floor, say) ] containing(wraps) anagram of(… nuts) ROUND.
Answer: The trademark name, once, of an automatic washing machine, hence the definition in the clue. It is now used as a common name for a place open to the public where one may wash clothes in coin-operated machines.

16 They might produce arts with models (3,7)
OLD MASTERS : Anagram of(produce) [ARTS plus(with) MODELS].
Defn: Collectively, the skilled painters in Europe before about 1800, who produced, well, art. A WIWD (wordplay intertwined with definition) clue.
19 Experienced audio novel (4)
KNEW : Homophone of(audio) “new”(novel/original).
20 Some characters in Tristram Shandy are flipping clever! (5)
SMART : Hidden in(Some characters in) reversal of(… are flipping) “Tristram Shandy“.
21 Rugby player’s speed is key (9)
BACKSPACE : BACK(a rugby player who takes the position of a defender against the opponent team) ‘S + PACE(speed).
Defn: … on your keyboard.
23 One swallowing tablet and rubbish synthetic material (7)
ACETATE : ACE(one, derived from the playing card with the value of 1) containing(swallowing) [ E(slang for the drug Ecstasy, which is taken in the form of a tablet/pill) + TAT(rubbish/tasteless clothes, jewellery or ornaments) ].
24 Covers of sublime track in Beach Boys’ territory (7)
SEASIDE : 1st and last letters of(Covers of) “sublime” + [ A-SIDE ](the track that is promoted on one of the two sides of a vinyl audio recording).
Defn: … without the capital letters. But of course, the Beach Boys were a pop group who started out singing surfing songs.
25 Model welcomes tip for tantric arousal (11)
STIMULATION : SIMULATION(a model imitating a situation or process) containing(welcomes) 1st letter of(tip for) “tantric“.
Down
1 Bedroom items, perhaps sketched bosoms? (6,2,7)
CHESTS OF DRAWERS : CHESTS(bosoms/breasts) OF(done by/sketched by) DRAWERS(people who draw/sketch).
2 Setter affectedly touching fabric (5)
MOIRE : MOI(an affected way for the setter to refer to himself/herself, instead of the plain “me”) + RE(with reference to/touching on).
3 One’s blown last of moola, air con needing repair (7)
OCARINA : Anagram of(… needing repair) [ last letter of(last of) “moola” + AIR CON].
Defn: …, ie. a wind instrument

4 Educational opportunity for everyone is canned (5-2)
TEACH-IN : EACH(for every one) contained in TIN(in a tin/is canned).
5 They add colour to online book (1-7)
E-NUMBERS : E-(prefix denoting an item that is electronic) + NUMBERS(book in the Bible).
Defn: Codes for food additives used in the EU and EFTA, that were first used for food colouring additives.
6 Average, struggling Inter Milan twice letting in a sitter? (15)
PARLIAMENTARIAN : PAR(an average/a normal or usual amount/a standard) + anagram of(struggling) INTER MILAN containing(… letting in) 2 x(twice …) A.
Defn: … in the House of Commons or Lords.
7 Youngster’s tucked into cake and salad as a working rule (10,3)
PARKINSON’S LAW : SON(a youngster)‘S contained in(tucked into) PARKIN(a type of dark gingerbread originally from the north of England) plus(and) SLAW(coleslaw/a salad dish of raw cabbage, carrots and other vegetables).
Defn: The adage “work expands so as to fill the time available for its completion”.
8 Cleaner animals show distress, seized by nurse (6,7)
CARPET SWEEPER : PETS(domestic or tamed animals kept for companionship or pleasure) + WEEP(to show distress/cry) contained in(seized by) CARER(a nurse/one who attends to the sick, infirm or young).
15 Performers with elevated pitch, primarily Italians? (8)
CASTRATI : CAST(a group of performers on stage or in a movie) plus(with) reversal of(elevated, in a down clue) TAR(pitch/material used for road-making, for example) + 1st letter of(primarily) “Italians“. A clever WIWD clue.
17 Kind of cross about clever dramatic scene (7)
TABLEAU : TAU(a kind of cross shaped like “T”, and so-called from the Greek letter “tau”) containing(about) ABLE(clever/skilled).
18 Means to get around bodily pain mostly fake (7)
RICKSHA : RICK(a slight sprain or strain in the neck or back) + “sham”(fake/false) minus its last letter(mostly …).

22 Holy man‘s morning in Westminster? (5)
SWAMI : AM(abbrev. for “ante meridiem”, the period of the day before noon/morning) contained in(in) SWI(SW1, the postal code for Westminster in London, with the Roman numeral substitution for 1).
Thanks Picaroon and scchua
7d was FOI as I remembered that Cole’s Law is “sliced cabbage in mayonnaise”. I needed your parsing for the ASIDE part of 24a.
Favourite was BACKSPACE.
Pedants’ corner: although some “E-numbers” are colouring agents, most aren’t – see here.
Thanks Picaroon and scchua.
The last few, as you say, were a bit of a struggle (RICKSHA and SEASIDE, for me.
I liked 16a – is it not almost an &lit?
Enjoyable puzzle
I enjoyed the humour in this puzzle. My favourites were KITTENISH, CHESTS OF DRAWERS, BACKSPACE.
RICKSHA was a new spelling for me, and Parkinson’s Law was a new phrase/name for me.
I failed to solve E-Numbers – I don’t think I had ever heard of them before.
Thanks Picaroon and scchua.
Thanks Picaroon & Scchua, enjoyable set of clues. Carpetsweeper arrived at circuitously by building up carp, weep, and er/sr for nurse. Not quite right as parsed above, but enough to get it. Appreciated 10a and 23a more, because the crossers were so unhelpful.
Not-ok also good, I appreciate the maxim ‘less is more’. Tau as kind of cross new, and will have to get used to ‘key’ as it appears more. Long time since seeing old Parky’s law.
Cruisy for a Friday I thought, though took ages and all crossers to remember that Law. Kittenish similar, ok once I stopped trying to put something meaning ‘put on’ around ten, d’oh. Great puzzle Picaroon, and thanks Scchua (great cartoon).
Great puzzle. Couldn’t parse the AIR in AQUARIA; loved PARKINSONS LAW and CASTRATI – very clever. Many thanks to P & s.
Slow to start on this one but got going with Chests of drawers. Then a steady solve.
LOI was MOIRE. Parliamentarian was surprisingly slow to come, too.
Thanks for the parsing of -aside in Seaside.
Good puzzle.
Thanks to Picaroon and to scchua.
Enjoyed this, particularly the clever CASTRATI which was first one in but I only got the definition so thank you for the full parsing.
Amused by the rather old fashioned references : LAUNDROMAT and CARPET SWEEPER. You don’t see COMP very often now either. AQUARIA was last one in – doh!
Loved the pictures; we also looked up MOIRE as Mr H always points out the Moire fencing along the M6.
Much easier than yesterday but just as much fun.
Thanks, P and S.
I found this fairly quick by Picaroon’s standards, but as always enjoyed it a lot
Thanks to Picaroon and scchua
Thanks for the blog, scchua.
My favourites were AMERICA, SMART [flipping clever!], MOIRE [because that use of ‘moi’ always makes me smile and, of course, CASTRATI – wonderful surface.
I spent a moment or two wondering how NOON could mean ‘retreat’.
I’ve never had to write ‘tenish’ – although I might say it a lot – but I think I would give it another ‘n’. That’s an observation, not a quibble.
Many thanks, Picaroon – I really enjoyed it.
ooh lots of that was very clever! do-able but clever. I did enjoy the nearly &lit clues which I thought were great examples of pushing the boundaries of the rules – they worked, were solvable and satisfying but not perfectly &lit or defined. Again, like yesterday, it’s all personal opinion but I loved the challenge here and the inventiveness and that, to my mind, justified the variation away from norms.
Stimulation had a great surface, e-numbers made me laugh when I saw it, and blimp read very smoothly. Parkinson’s Law was a fave, and too many others were great so thank you Picaroon and also thank you scchua for unraveling the a-side for me, and the teach-in, which I had but unparsed.
I’ve never known quite such a puzzle where I’ve written in the answers then looked for so many of the explanations afterwards. But what a wonderfully illustrated offering for us all this morning, Scchua, many thanks!
Good swashbuckling fun from the Pirate,
as always. Thanks to him and Scchua.
Was it one of C. Northcote Parkinson’s
secondary laws to always appoint two
deputies; so busy squabbling that your
position is safe ?
Enjoyed this, some less familiar words but all fairly clued.
I did wonder about re=touching, nook=retreat and the fact that old masters definitely will not produce any art.
Eileen @10 ‘Tennish’ conjures up an image of Sean Connery at Wimbledon!
Thanks to Picaroon and scchua.
robert @ 14; you’d better get used to re = touching – it crops up quite often.
Eileen @ 15 Yes, one of a number of regularly used devices where the justification requires a compound phrase (as in ‘touching on’ above – which would be fine to my ears) which always seems odd to me.
Not relevant to the clue, but “blimp” was also “a small, nonrigid airship or dirigible, especially one used chiefly for observation”. The fat colonel was named after that.
robert 16 Hmm, interesting – it’s ‘touching on‘ that sounds odd to me: ‘touching’, in all my dictionaries is defined as ‘on the subject of, relating to, concerning’, or similar. To add a further preposition seems tautologous.
‘You say “neether”, I say “neither”, let’s call the whole thing off’ (the Gershwins).
In case you missed it – Tramp’s footnote on the blog of his Thursday puzzle:
“From today’s Times:
Leave to see the sights of US city, adopting new water transport” = GONDOLA.
Neil”
[The Times! O tempora, O mores]
My beautiful laundromat.
Thanks Picaroon and schchua——
Not all sons are youngsters.
I’m one and I’m 78.
Eileen@20
Fair point.
Case for appeal back on good new ground
Thanks to sschua and Picaroon
Good fun as always with Picaroon. I tried LOCKS and PACK at 21a before I realised I was using the BACKSPACE key to erase my previous guesses – that gave me a laugh.
Yes, a good one, entertaining and well up to Picaroon’s high standards. Dunno why, but I really struggled to get going properly. After two passes through the clues I had about five solutions. Then I got COMPOST HEAP and I was away. LOI was BACKSPACE, which I should have seen much sooner.
Thanks to Picaroon and scchua.
Eileen @ 18 Thank you, your comment intrigued me as I thought the idiom ‘touch on’ was pretty well established, I checked a couple of dictionaries and touching is there as you described (interestingly, Chambers online had it as ‘old usage’), I shall wonder no more on that one.
Thanks to Picaroon and scchua. Lots of fun. Like others I had trouble parsing SEASIDE and also with the spelling of RICKSHA.
robert @26 – yes, my SOED has it as Late Middle English: I’m pretty sure I’ve met it in Shakespeare but can’t pin down any instances.
Thanks to Picaroon and scchua. I think I had more trouble with this than many others seem to have experienced. While a lot fell in quite readily, I generally struggled with the rest. However got there in the end with parliamentarian, ricksha and laundromat last in. Overall good fun and I liked backspace, E numbers and moire. Thanks again to Picaroon and scchua.
I started this last night, picking up the last half-dozen this morning. Having myself written this clue once:
Single out to the audience (5)
I had no trouble with SEASIDE. But I hadn’t heard of BLIMP, which I put in without understanding. Thanks for explaining.
Another excellent puzzle from Picaroon with lots of ticks and three ?s that I needed scchua’s parsing for – the QUA bit of AQUARIA, the whole of SEASIDE (now my cotd) and all but the I of CASTRATI – the last two I clearly didn’t try hard enough as like all the best clues they are obvious with hindsight. Many thanks to Picaroon and scchua.
We’ve had RICKSHA before but I still struggled with it. I liked most of this but I was a bit slow in completing it. I liked KITTENISH and OCARINA. The latter is a lovely word.
Thanks Picaroon.
A dnf for me, as I was not familiear with either E-NUMBERS or SW1 for Westminster. A lot to like, though, even in defeat. I especially liked KITTENISH and CASTRATI and chuckled at MOIRE when I was finally able to parse it.
Thanks, Picaroon and Scchua.
Thanks very much for the blog, which i needed today! But could anyone explain WIWD in the explanation of at 15d?
Mike @34
See scchua’s blog @16a
We thought this was Picaroon at the top of his game, mouthwatering good.
Everything’s so silky smooth. The writing style is so natural, almost effortless.
I smiled at 12ac, as it was the ideal companion to my own 14dn in the Independent 9,973 (29 Sep 2018).
Some setters wouldn’t have added an apostrophe to ‘Youngster’ in 7d but Picaroon did. And he is fully right, avoiding an indicator written in the past tense!
Thanks scchua (for the blog) & Picaroon (for the brilliance).
14a, Sil?
I found this as challenging as yesterday’s and every bit as good. My particular favourites were COMPOST HEAP, BLIMP, BACKSPACE, SWAMI and CARPET SWEEPER.
Many thanks to Picaroon and Scchua.
Thanks muffin
Alan B @ 38 (following from yesterday)
There are numerous abbreviations in common usage that (I believe, haven’t checked ‘em all) don’t appear in dictionaries, eg W D L for win/won, draw, lose/lost. And S = Society frequently appears, but I don’t think I’ve ever seen it other than as part of a multi-letter abbreviation.
And I discovered another one yesterday, in a summary of cricket matches: A for (match) abandoned. Wonder how long it’ll be till that appears in a crossword.
Took me a while but I got there in the end. Enjoyed the tussle but can’t believe I was so slow to get clues like 19a KNEW, my LOI. All my favourites have been mentioned, though I want to particularly highlight how much I liked the Beach Boys at the SEASIDE (24a) and am now playing several of their A-sides in my head (mind you, I did spend ages trying to fit in CA for California)! [BTW, I also wrote TENNISH? beside 11a KITTENISH, Eileen.]
Thanks to all previous posters, to scchua for the detailed blog and to Picaroon for a great puzzle.
Thanks scchua and Picaroon. I failed with NOON for 13, ‘to noon’ can mean to take a rest at midday, so almost.
[I also tried to fit in UNDIES to 14a LAUNDROMAT – “wraps round nuts” – well, some of the letters fitted something to do with laundries. However eventually the crossers meant I had to give up on that rude idea.]
Simon S @40
Thank you for your further thoughts on abbrevations (a never-ending topic!).
Julie @41,43
Thank you for your entertaining mimi-story on LAUNDROMAT. I actually had LAUNDRYMAN at first, which fitted the crossers perfectly at the time but had the distinct disadvantage of not fitting the wordplay.
I would contend that CASTRATI is in fact an &lit since its whole is wordplay (as well as a fine definition). Or am I missing something? Great clue, as was SEASIDE.
Many thanks both and all.
Slow but steady except for the top right corner, dnk qua and missed the colour reference in 5d. Strange but I also put in Laundryman for 14a before realizing that 8d was Carpet Sweeper.
Good puzzle Picaroon and excellent blog.