Solution to 27A has been deliberately left unsolved and is to be answered only by a non-regular / novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.
ACROSS
1 Swelling around anus with red rash essentially (4,3,6) PURE AND SIMPLE {P{ANUS+RED}*IMPLE}
8 Twitch after operation of the eye (5) OPTIC {TIC}<=>{OP}
9 Zero jobs for failures (9) OMISSIONS {0}{MISSIONS}
11 Feverish tot with dengue clutching one's mum (6-4) TONGUE-TIED {TOT+DENGUE}* over {1}
12 Money in wad turned soggy (4) DAMP {PA{M}D}<=
14 English expert stifles till one quits in final stage of chess match (7) ENDGAME {E}{N{DiG}AME}
16 Remained embarrassed after one passed wind (7) MEANDER REMAiNED*
17 Relative on a bit of rum, getting hazy (7) UNCLEAR {UNCLE}{A}{Rum}
19 One getting bowled over by author around lunchtime in exotic inn (7) NINEPIN {PEN<=}{1} in {INN}*
22 Decoy having sex with English rogue for information (10) LITERATURE {LURE} over {IT}{E}{RAT}
25 Steals boxes, bringing back container with king's ornaments (9) NICKNACKS {NICK{CAN<=}{K}S}
26 Edged ball close to slips, caught by dive to the left (5) NOSED {O}{s..pS} in {DEN<=}
27 Imperious century, batting second with resolution (13) ?O?D?S?E?D?N?
DOWN
2 Not properly adjusted, loose nut on universal joint rotates (7) UNTUNED {NUT*}{U}{DEN<=}
3 Stimulated by snorting cocaine, revolting individual at university went berserk (10) ENCOURAGED {O{C}NE<=}{U}{RAGED}
4 Fool stealing gold in French commune (5) NIORT {NI{OR}T}
5 Superhero dashes backwards, saving skin (6-3) SPIDER-MAN {NIPS<=} over {DERMA}
7 Fat around body part, revolting in skintight garment (7) LEOTARD {L{TOE<=}ARD}
10 Smashing mean monitor (11) SUPERINTEND {SUPER}{INTEND}
13 Supported fantastic Indian team (10) MAINTAINED*
15 Eastern academy assembling precise listening devices (9) EARPIECES {E}{A}{PRECISE*}
18 Liqueur given by scoundrel starting to attract associate in firm (7) CURACAO {CUR}{At...t}{C{A}O}
23 Losing head, anxious about university result (5) ENSUE {tENS{U}E}
24 Teen idol entertaining American city (4) ENID [T]
Reference List
Operation = OP, Money = M, English = E, Till = DIG, Lunchtime = 1, Fine = F, Sex = IT, King = K, Dive = DEN, Universal = U, Joint = DEN, Gold = OR, Husband = H, Eastern = E, Academy = A, Firm = CO, Associate = A, University = U




