28090 Thursday, 23 September 2021 A whiter shade

My steady 30 minute solve has a typo, so doesn’t properly count, but indicates that I found some of this on the tricky side. By my reading, we have two clues which could have alternative definitions and parsings, which is at least unusual, but not really a difficulty. I still have a couple of clues I’m not sure of, though the entries are unmistakeable.
Not everyone will be familiar with the religion cited, though you can trust the wordplay. The saint should be okay. Purists will object to some minor Guardianesque cross referencing, but it’s not too tricky. One nice touch is to have the playwright in the close vicinity of a word derived from one of his best known plays.
So I’ve done what I can to explain what we have, and present my usual clues, definitions and SOLUTIONS

Across
1 Legal officer has trouble breaking strike (7)
BAILIFF To trouble is to AIL, which breaks (is inserted into) BIFF for strike
5 Game withdrawing place for quiz buff (3,2)
RUB UP So the definition is not that sort of buff, unless it’s someone expert in Polish. The game is R(ugby) U(nion) then you have withdrawing as a reversal indicator, and PUB as a common place for a quiz – um – reversed.
9 Writer phones — biographer rings back (5)
IBSEN The words phoNES BIographer ring the reverse (back) of the mostly depressing writer.
10 Doctor, initially kept in barracks, works in kitchen? (9)
COOKBOOKS Doctor is a verb here, so COOK as in the books, followed by the initial letter of Kept within BOOS for barracks, not the accommodation but the catcall variety.
11 Anchor held by hideous, headless phantom (7)
GHOSTLY Adjectival phantom, as in The Phantom Menace (apologies if you despise the movie). Anchor is HOST, more I think an American usage as the person that holds together a TV show. It’s “held” by UGLY for hideous without its first letter, being headless.
12 Marked student’s first, abridged unseen? No (7)
SPOTTED One way of reading this clue is that we have two definitions split by the wordplay, which would be student’s first, S and POTTED for abridged. Both marked and unseen no(t) are adequate definitions. Or it could be that we’re meant to read that it’s potted that’s not unseen. Take your pick.
13 Aid when sewing up chinos in fragments (10)
PINCUSHION At last a nice, comfortable anagram (fragments) of UP CHINOS IN.
15 Right to remove mouse’s head from trap (4)
ORAL Right is MORAL, remove the M(ouse’s) head. Much time lost trying to remove the M from a trap of some description to give right.
18 Husband and child after return fare (4)
NOSH Another reversal (return) of H(usband) and SON for child.
20 When unlikely to be welcomed into a hotel owned by us? (2,3,5)
AT ALL HOURS I have this as an &lit, but I’m open to persuasion. TALL is the stand in for unlikely (tall story and so on) “welcomed into” A H(otel) and followed by OURS for owned by us. Aren’t hotels (at least the better ones) supposed to welcome you whenever you turn up, even if it is “at irregular hours, especially late hours” (Chambers definition of our entry)?
23 Reason given to those being punished (4,3)
WHAT FOR Informally (Chambers) what for is “punishment, chastisement, as in I’ll give you what for” So I believe we have a double definition.
24 Tossing carrot to black kid in Golf (7)
BRIBING We have B(lack) RIB for kid, IN in plain sight and G(olf) in NATOspeak.
25 Developed from birth in US, different from US! (9)
UNBRITISH Our second anagram (developed from) BIRTH IN US. Everyone doing the crossie is assumed to be British for the duration. I was going to quote the famous assessment of early submarines as “underhand, underwater and damned un-British” but careful research shows that Admiral Sir Arthur Wilson used the term “un-English” possibly to the annoyance of the Scots and Welsh.
26 Swindlers, at least eight, after dope … (5)
SPIVS The SP short for Starting Price, is a Woosterish term for gen or dope on the nag’s chances. IVS is Roman for fours, so the minimum for the plural would be two of them. Took me a while.
27 … one more coming in to give out pot (5)
DIXIE Surprisingly, a word of Hindi/Persian origin for a military cooking pot. Referring back to the 8 in the previous clue, we have one more, IX in Roman. In DIE for to give out.
28 Article removed from slope off ramp (7)
SLIPWAY Slope off as a verb is to sneak away, or here SLIP AWAY, with one of the A articles removed.

Down
1 Musician with good news for impatient undergraduate? (7)
BASSOON So the good news briefly given to out impatient undergrad is BA’S SOON.
2 Aug 1 isn’t especially for a saint (8)
IGNATIUS At least two to chose from, the better known one being Loyola, founder of the Jesuits. And our third anagram (especially) of AUG I ISN’T. Not that it matters, but Ignatius Loyola’s feast day is one day before Aug 1.
3 Irritating incident that can harm you at first (5)
ITCHY I’m OK with the definition, and the Y comes from You at first. Why ITCH is an “incident that can harm” I haven’t yet worked out to my satisfaction.
4 Support coming from old Labour leader’s flunky (9)
FOOTSTOOL The old Labour leader who as well as being a previous Labour leader was old when he was, is Michael FOOT. His flunky is therefore FOOT’S TOOL
5 Outlaw to plunder gold, lifting unknown amount (3,3)
ROB ROY Indeed a Scottish outlaw, romanticised and embellished by Walter Scott. Plunder gives ROB, gold is OR, which is reversed (lifting) and Y is our “unknown”
6 Fish from lake caught by one out on it? (7)
BLOATER A (dead) (dried) (smoked) herring, but still a fish. L(ake) is caught in BOATER, who might indeed be out on the lake.
7 Displaying calm — no one was affected (5)
POSED Another where there are two possible definitions at either end of the clue. But I think the better reading has displaying calm to give POISED, from which the I (one) is removed (no one).
8 What’s most impressive about albatross spawning mutant? (8)
WINGSPAN Well, 12 feet is pretty impressive for a bird. And it’s also our fourth anagram (mutant), of SPAWNING
14 Random greeting to Romeo by young lady (3,2,4)
HIT OR MISS Re-spaced, it’s HI TO R(omeo) and young lady MISS
16 Army officer and doctor, each ringing when desperate (4-4)
LAST-GASP So you have a L(ieutenan)T and a G(eneral) P(ractitioner) each “ringing” AS for when.
17 Powerful feller appearing in series 12 (8)
CHAINSAW Cute definition. CHAIN from series, SAW referring back to 12a SPOTTED.
19 Pensioners putting up singular fight for platform to be heard? (7)
SOAPBOX Pensioners are OAPS. Put up the S(ingular) to the front, add BOX for fight.
21 Public service, something with no end, no beginning (7)
UTILTY Like Water Works and Electric Company. I assume something with no end (purpose) is a FUTILITY, remove its beginning.
22 Workplace no longer being kept ready? (6)
OFFICE Something being kept ready for use (such as champagne) is ON ICE. So if it’s no longer being kept ready it’s….
23 Did snake bite? (5)
WOUND two definitions of homographs.
24 Belief, revolutionary one, obsessed captain (5)
BAHAI Strictly Baha’I, a syncretising religion originating in Persia and with a rather splendid temple dominating Haifa. I (one) and our obsessed Captain AHAB (Moby Dick) are reversed (revolutionary)