Solution to 1D 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.
Open for anyone to answer, if not solved by 1 PM.
ACROSS
1 Fit to steal (11) APPROPRIATE [DD]
9 Say, one from Nigeria can receive fair play (7) AFRICAN {CAN+FAIR}*}
10 Displays a dog's head inside? No, it's dogs (7) SHADOWS {SH{A}{Dog}OWS}
11 Topic of those people - to procure drugs (5) THEME {THEM}{E}
12 Secure right inside, bad debts heartlessly collected (9) HARVESTED {HA{R}VE}{DEbTS*}
13 First lady has book business (5) EVENT {EVE}{NT}
15 Holy man worried, people tense with announcement (9) STATEMENT {ST}{ATE}{MEN}{T}
18 Say, youngsters have support, trouble's overcoming hesitation (9) TEENAGERS {TEE}{NAG{ER}S}
21 Bengali gentleman's at a corner, observe (5) SENSE {SEN}{SE}
22 Quality of tea? Light at the end in stock, right! (9) CHARACTER {CHA}{RAC{l..hT}E}{R}
24 Sisters are full of love for places, things, animals etc (5) NOUNS {N{O}UNS} Definition by example
26 Painful back, one on wear (7) EROSION {SORE<=}{1}{ON}
27 Senior struggling to control one who is more loud (7) NOISIER {NO{1}SIER*}
28 Underground society in a country (11) NETHERLANDS {NETHER}{LAND}{S}
DOWN
1 Statecraft by individuals at Thailand is flat (9) A?A?T?E?T ()
2 Fantastic, super pouch (5) PURSE*
3 Group put fish in box, right? No, the other way round (9) ORCHESTRA {OR{CHEST}{R}A} No Anind for OARfish
4 Estates managed by revolutionary's primarily socialistic (7) RANCHES {RAN}{CHE}{So...c}
6 Eradicate cholera selectively, not entirely (5) ERASE [T]
7 Neither partner's article on force pertains to direction (8) NORTHERN {NOR}{THE}{RN}
8 Employed? Outspend frequently (4) USED {oUtSpEnD}
14 Cruel Eva tortured hiding in lift (8) ELEVATOR [T]
16 Key German city on trial to end racism primarily (9) ESSENTIAL {ESSEN}{TrIAL}
17 Arrest Sue distributing fortunes (9) TREASURES*
19 Former lover taking money at cantonment banks terminated (7) EXTINCT {EX}{TIN}{Ca...nT
20 Saint called Chief Executive? It's odd (7) STRANGE {ST}{RANG}{Ex...e}
22 Bolt loses lead in team (4) CREW sCREW
25 University (Oxford) joins new coalition (5) UNION {UNI}{O}{N}
Reference List
Drug = E, Right = R, Book = NT(New Testament), Holy man = ST(Saint), Tense = T, Corner = SE, Society = S, Old = O, Force = RN(Royal Navy), Oxford = O, New = N