No 12235, Thursday 08 Feb 2018, Neyartha

Answer and annotation for 19D left for a rookie commenter till 10 AM.

ACROSS
1   US government agency protecting investors backing revolutionary coils in a disgusting and corrupt place (8) CESSPOOL {SEC<=}{LOOPS<=}
5   Cooking aid for a dressmaker (6) BASTER [DD]
9   Tapestry covering the no-good queen's orchestrators (9) ARRANGERS {ARRA{NG}{ER}S}
11 Mark for insertion of a promised reward to the auditor (5) CARET (~carrot)

^

12 Cooking aid for the trespassing hunter's fish (7) POACHER [DD]
14 Run out with a parade decoration to the ship (7) STEAMER STrEAMER
15 Lee sent creep out for something achievable using, say, Skype? (12) TELEPRESENCE*
17 Pointless to burn acetone and granite mixture after Edward leaves to get an antiknock measure (6,6) OCTANE RATING {ACETONe}* {GRANITe}*
20 One put on it might be heavily criticised (7) GRIDDLE [CD]
22 Spark off anger about the spin after the name comes up (7) INSPIRE {IRE} around {(+n)NSPI(-n)}
23 Letters from Laskhmi, a minor, in an American city (5) MIAMI [T]
24 Aircraft component in a pallet gets disassembled (9) TAILPLANE*
26 Pressure situation that might result in a whistling food-preparation aid? (6) COOKER [CD]
27 Worried Edward's behind the article on the holy book (8) AGITATED {A}{GITA}{TED}

DOWN
1   No answer to Pascal's transformation of the fasteners (6) CLASPS PASCaLS*
2   Cynical actors sheltered by Rhode Island in an enclosed space (9) SARCASTIC {SA{R{CAST}I}C}
3   Cooking aid found with the speaker's velvet-like fabric (3) PAN (~panne)
4   Have a disproportionately large percentage of pre-teen rovers at sea (13) OVERREPRESENT*
6   Military forces capture a revolutionary bottling gas for people extremely hostile to each other (11) ARCHENEMIES {AR{CHE}{NE}MIES} What's the role of 'bottling'?
7   Play a stringed instrument as the leaders of the Huns reveal undated manuscripts (5) THRUM Acrostic
8   Delay in wages after wife goes out for a short time (6) RETARD RE(-w+t)TARD
10 Arranging the gymnast's tie is tricky (13) SYSTEMATISING*
13 Dutch province attracting first-class bridge players with a type of sauce (11) HOLLANDAISE {HOLLAND}{A1}{SE}
16 Aware of the article under the broken sign kept inside a small bed (9) COGNISANT {CO{SIGN*}{AN}T}
18 Flag a microbe revealing something related to asexual reproduction (6) AGAMIC [T]
19 Bet compounded by the departure of a couple of Orientals (6) ?E?E?D (Addendum - DEPEND DEePENeD - See comments))
21 Depiction of energy transforming into an egg shows the last stage of an insect's metamorphosis (5) IMAGO IMAG(-e+o)O
25 Crown lifted to reveal a vessel (3) POT<=

GRID