ACROSS
8 - Grab a bunch of eggs (6) - CLUTCH [DD]
9 - Set back after lying outright (8) - POSTPONE {POST}{PrONE}
10 - Expressed ire about rank superficial item (8) - EYELINER (~ire){EYE{LINE}R}
11 - August: only month not somehow hot (6) - SOLEMN {SOLE}{MoNth*}
12 - Consider tic-tac-toe a non-U.K. recreation (4,4,7) - TAKE INTO ACCOUNT*
14 - Dislike a museum? Good to skip ahead then (7) - ALLERGY (-g)ALLER(+g)GY
19 - Peculiar British contraption for showing a measure of global
warming (6,9) - CARBON FOOTPRINT {B+CONTRAPTION+FOR}
22 - Spread the word before a church (6) - PREACH {PRE}{A}{CH}
24 - Associate welcomed company’s revolutionary move (8) - RELOCATE {REL{OC<-}ATE}
25 - Show admiration for the learned? Me too (8) - LIKEWISE {LIKE}{WISE}
26 - Cures provided by multipurpose rum shops (6) - SERUMS [T]
DOWN
1 - Agree to take part in soccer perhaps (4,4) - PLAY BALL [DD]
2 - Statesman, a teetotaller outside beer? On the contrary, takes
Ecstasy (6) - ATTLEE {A{TT}LE}{E}
3 - Insane hang-gliding stunt (10) - SHENANIGAN*
4 - One flier in two arguments (7) - SPARROW {SPAR}{ROW}
6 - Make clear littering pollutes (5,3) - SPELL OUT [DD] (Addendum - SPELL OUT* - See comments)
7 - He’s single (3-3) - ONE-MAN [CD]
13 - Big-time operator. IST may be (10) - CAPITALIST {CAPITAL}{IST}
15 - Took to assembled miracle beds heartily (8) - EMBRACED {assEMBled}{miRACle}{bEDs}
17 - With rat, fast termination is a possibility (2,2,4) - IN NO TIME tErMINaTION* (See comments)
18 - Conservative approach to envy (2,5) - GO GREEN [DD]
20 - Nifty run out breaks opening (6) - ADROIT {AD{RO}IT}
21 - History book (6) - RECORD [DD]