An enjoyable one from a Quiptic regular. Thanks to Hectence. Definitions are underlined in the clues.
Across
1 Comedian’s comeback about posh fellows gets laugh (6)
GUFFAW : Reversal of(…’s comeback) WAG(a comedian) containing(about) [ U(signifying “posh”;upper class) + F,F(abbrev. for “fellow”, twice) ].
4 Job on island for Pat, perhaps (7)
POSTMAN : POST(a job;a position of paid employment) plus(on) MAN(the island in the Irish Sea).
Defn: An example of which;perhaps is Pat, in the animated children’s television series shown on the BBC.

9 Spiteful false claims about debt (9)
MALICIOUS : Anagram of(false) CLAIMS containing(about) IOU(a signed document acknowledging a debt, from the pronunciation of “I owe you”).
10 One is taken in by crafty card sharp (5)
ACRID : I(Roman numeral for “one”) contained in(taken in by) anagram of(crafty) CARD.
Defn: … in smell or taste.
11 Cover band? (5)
LAYER : Double defn. 1: … over a surface, such as dust; and 2: … of material that is different from that above and/or below it.
12 Short jacket and bag for work (9)
BRIEFCASE : BRIEF(short) + CASE(a jacket;an outer covering).
13 Kick off again with skill after break (7)
RESTART : ART(a skill at doing a particular thing) placed after(with … after) REST(a break from activity).
15 Fabulous rampant beast described by quote (6)
EXOTIC : Reversal of(rampant;wild) [ OX(a beast) contained in(described by) CITE(to quote;to refer to, say, a passage, book or author) ].
17 Woman’s hat made from good French material (6)
BONNET : BON(French for “good”) + NET(a material;fabric of a uniform mesh).
19 Cobblers‘ first half own goal was hard (7)
HOGWASH : The 1st letter of(first) “half” + OG(abbrev. for “own goal”, in football) + WAS + H(abbrev. for “hard”).
Defn: …, which is slang for nonsense.
22 Tea bags and cake regularly put out in the wings (9)
BACKSTAGE : Anagram of(… put out) [TEA BAGS plus(and) the 1st and 3rd letters of(… regularly) “cake” ].
Defn: … in a theatre.
24 Virtue’s foremost in Christmas story (5)
NOVEL : The 1st letter of(…’s foremost) “Virtue” contained in(in) NOEL(Christmas).
26 Moderate a beta version (5)
ABATE : Anagram of(… version) A BETA.
27 Smart kitchen furniture not finished ahead of party (7,2)
DRESSED UP : “dresser”(kitchen furniture;a sideboard for storing plates and utensils) minus its last letter(not finished) placed before(ahead of) DUP(abbrev. for the Democratic Unionist Party of Northern Ireland).
28 Raise for worker briefly entering enclosure close to crocodile (7)
ENHANCE : “hand”(a worker, especially engaged in manual work) minus its last letter(briefly) contained in(entering) ENC(abbrev. for “enclosure”, to indicate document(s) included with a letter) + the last letter of(close to) “crocodile“.
29 Banks in Ecuador take currency commission (6)
ERRAND : The 1st and last letters of(Banks in;the enclosing letters) “Ecuador” plus(take) RAND(the monetary currency of South Africa).
Defn: An instruction to undertake a mission, in this case, a short trip to accomplish a specific purpose.
Down
1 Lightweight stroller’s better (7)
GAMBLER : G(abbrev. for “gram”, a very small weight) + AMBLER(one who strolls along).
Defn: One who places bets.
2 Female university students approach year positively (5)
FULLY : F(abbrev. for “female”) + U(abbrev. for “university”) + L,L(symbol on a plate signifying a learner driver, twice) plus(approach) Y(abbrev. for “year”).
Defn: …;totally, as in “he looked positively stunned”.
3 Find out a canister’s cracked (9)
ASCERTAIN : Anagram of(…’s cracked) A CANISTER.
4 Indifferent progress with intravenous drug (7)
PASSIVE : PASS(to progress;to move forward in space or time) plus(with) IV(abbrev. for “intravenous”, as with an IV drip in hospital) + E(abbrev. for the drug Ecstasy).
5 Stick with team (5)
STAFF : Double defn: 2nd: … in a particular organisation.
6 Drive back by river in carriage having a cocktail (9)
MARGARITA : Reversal of(… back) RAM(to drive, say, a vehicle forcefully against, say, another vehicle) + [ R(abbrev. for “river”) contained in(in) GAIT(carriage;the manner in which one walks) ] plus(having) A.
7 Persuaded to shift dung to rear of shed (6)
NUDGED : Anagram of(shift) DUNG plus(to) the last 2 letters of(rear of) “shed“.
Defn: Coaxed or gently encouraged someone to do something.
8 Search reservists turning up for battle (6)
COMBAT : COMB(to search carefully and systematically) + reversal of(… turning up, in a down clue) TA(abbrev. for the Territorial Army, now called the Army Reserve, the volunteer reserve force in the British Army).
14 Put brakes on bus for dawdler (9)
SLOWCOACH : SLOW(to cause a slowdown by putting on the brakes) + COACH(a single-decker bus used for longer journeys).
16 Runner regains form to chase gold (9)
ORGANISER : Anagram of(… form) REGAINS placed below(to chase;to go after, in a down clue) OR(golden colour in heraldry).
Defn: One who runs an event or activity.
18 Duo endlessly confuse with silly talk (7)
TWADDLE : “two”(duo) minus its last letter(endlessly) + ADDLE(to confuse someone).
19 Noted hospital’s energies died when I left (6)
HEEDED : H(abbrev. for “hospital”) plus(‘s;contraction for “has”) E,E(abbrev. for “energy”, twice) + “died” minus(when … left) “I“.
20 Dad wearing cap follows man to landing site (7)
HELIPAD : [ PA(informal term for one’s dad;father) contained in(wearing) LID(a cap, say, on a container) ] placed under(follows, in a down clue) HE(pronoun for a man).
Defn: … for a helicopter.
21 Furious when sailor’s idle (6)
ABLAZE : AB(abbrev. for “able-bodied seaman”, a sailor) + LAZE(to idle;to loll about).
23 Set off home with beer mug (5)
STEIN : Anagram of(… off) SET + IN(at home).
25 Spirit is very aged finally in conditioned oak (5)
VODKA : V(abbrev. for “very”) + the last letter of(… finally) “aged” contained in(in) anagram of(conditioned) OAK.
A couple of minor typos:
It’s the first and third letters of CaKe that complete the anagram fodder in BACKSTAGE.
It’s the last two letters of shED that complete NUDGED. (I bet there will be moaning about this…)
Very enjoyable puzzle today.
Thank you Hectence and scchua
Thanks Hectence and scchua
I had a fast start, but a surprisingly slow finish. I didn’t know ENC for “enclosure”, and my last two – PASSIVE and EXOTIC – I though were quite hard for a Quiptic. Several favourites, including ACRID, HOGWASH, ORGANISER and STEIN (though I think “for” would have better than “with” in this one).
Allow me to be the first to moan about “rear of shed” giving ED!
btw BONNET reminded me of the craze in Restoration England (1660s) of women wearing blue hats. Yes, it was a recurrence of the Blue Bonnet Plague! (The old ones are the best – or probably not, in fact)
Thanks Blaise. Typos corrected.
Thanks Hectence and scchua.
Like muffin @3 the finish took almost as long as the start.
Largely OK level for a Quiptic, but there were IMHO a number of inaccuracies or sloppy cluing:
‘first half’ doesn’t really mean ‘h’ [first of half]
I would think that ‘form’ as an anagrind is an imperative that should go before the fodder
‘rear of shed’ would normally be ‘d’
‘rampant’ is OK as a reversal indicator but not really suitable for this level of crossword
P.S. Chambers gives rampant as rearing, so possibly better in a down clue.
After a fairly good week last week I was disappointed to have two clues unanswered: in retrospect I should have managed BRIEFCASE (completely on the wrong track with that one) which might have given me COMBAT, but my brain cells were running dry after what I thought was quite a tough Quiptic. EXOTIC and ERRAND stand out as answers that were more or less guesswork.
Leaving my frustration with self aside, I thought there were a number of good/fun clues here, and thanks to Hectence for the experience. Thanks also to scchua, whose style of blogging the answers I find particularly clear and helpful.
Robi @5, I think the anagram indicator ‘form’ (in 16d) is a nounal one, similar to ‘version’ in 26ac.
Not everyone is a huge fan of such indicators (including moi) but some time ago I decided (for myself) that if “X nounal anagrind” can mean “nounal anagrind of X”, it’s fine.
Agree with you about ‘first half’ = H and ‘rear of shed’ = ED.
But apart from these two oddities a good crossword, albeit perhaps at the harder end of the Quiptic spectrum.
Thanks Hectence & scchua.
The first Quiptic I’ve tried and it took longer than the day’s Cryptic? Unconvinced by rampant as a reversal indicator, but any slowness elsewhere was of my own doing. Well, it is late, that’s my excuse anyway.