Solution to 18A has been deliberately left unsolved and is to be answered by a non-regular/novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.
Open for anyone to answer, if not solved by 1 PM.
HIJKLMNO Pronounced
ACROSS
1 Development environment that boss nearly destroyed to grasp a bit of programming (4,4) STOP BATH {THAT+BOSs}* over {Pr...g}
6 Surprise for woman expecting escort? (6) SHOWER [DD]
9 Setter going for a social media interaction with Victoria, perhaps (4) LAKE L(-i+a)AKE
10 Some elaborate trap to teach obscure grammatical term? (10) TETRAPTOTE [T]
11 Oh, let's go back for a campus gathering (6) HOSTEL {OH<=}{LETS<=}
12 Gang, in memoir, was regularly retreating for sport (8) SWIMMING {GaNg+In+MeMoIr+WaS}<=
13 Writer got sharply panned (10) STYLOGRAPH*
17 Collect fingerprint pattern after returning (4) POOL<=
18 Old bird circling cloud or a kind of delivery service? (4-2-4) D?O?-T?-D?O?
20 Set out quinoa around five following chef's first dish (3,2,3) COQ AU VIN {QUINOA}* over {V} after{Chef}
24 Made dry Indian crispy chicken starters, gobbled up with daughter (10) DESICCATED {DESI}{Cr...y}{Ch...n}{ATE}{D}
26 Welcome husband's distress (4) HAIL {H}{AIL}
27 Disentangle gunk and snot after blowing noses (6) UNKNOT {gUNK+sNOT
28 Spooner's young boy, batter with poor judgement (3,5) BAD TASTE (tad baste to bad taste)
DOWN
2 Quite a fort! Wonderfully hosts a small party (3,3,3) TEA FOR TWO [T]
3 Fold coat, bottom to middle (5) PLEAT PL(+e)EAT(-e)
4 Essentially, can't I logically use this operation to convert, say, 1 to 10? (7) ANTILOG [T]
5 How to prune butts, becoming attractive (3) HOT {HOw}{To}
6 Unoriginal southern liberal (7) SLAVISH {S}{LAVISH}
7 Made improvements in newspaper column about model I.I.M.s, with editing (9) OPTIMISED {OP ED} over {T+IIMS}*
8 Scoffed at faceless men on ecstasy (5) EATEN {AT}{mEN}<=>{E}
12 Squabble over private resort area (3,4) SPA TOWN {SPAT}{OWN}
14 All muddled, old language includes old pronunciation of R as L (9) LALLATION {ALL}* {LATIN} over {O}
18 Voted crankily to accommodate company housing for pigeons (7) DOVECOT {DOVE{CO}T*}
19 Lacking advanced auxiliary supports, ramshackle hut collapsed noisily (7) THUDDED {aADDED}<=>{HUT*}
21 Main article chases CEO's replacement (5) OCEAN {AN}<=>{CEO}*
25 Save up for boat (3) TUB<=
Reference List
Son = S, Quiet = SH, Daughter = D, Husband = H, Southern = S, Model = T, Ecstasy = E, Old = O, Ordinary = O, University = U, Advanced = A
