Across:
8 Rob the (rob the = BOTHER) plan (= anagram indicator) to get up someone’s nose (BOTHER),
9 Lounge (lounge/laze = LOLL-) has one (-I-) soft drink (-POP) (LOLLIPOP) for local sucker (LOLLIPOP),
10 Baker leaves breakfast (“baker” leaves “breakfast” = fast = FAST) to go hungry (FAST),
11 Pirates on a (pirates on a = SEPARATION) craft (= anagram indicator) in Split (SEPARATION),
12 Lost (BEATEN) hammer (BEAT-), to be fairly (half of) frank (open) (half of “open” = -EN) (BEATEN),
14 In the department responsible for cover-up (MENSWEAR), some people (MEN-) take a vow? (a vow = avow = -SWEAR) (MENSWEAR),
15 Divorce (LEGAL SEPARATION) leads to 22 across (“legal eagle” = LEGAL) and 11 across (“separation” = SEPARATION) (LEGAL SEPARATION),
18 For each (PER-) court action (-SU-E) over advertisement (-AD-) (PERSUADE) for local, soft soap (local “soft-soap” = PERSUADE),
20 Redhead (red head = -R-) consumed by drink (LA-GER) (LARGER) and more stout (LARGER),
22 Barman (LEGAL EAGLE) is allowed (LEGAL) to get something the swingers want (golf swingers want an EAGLE) (LEGAL EAGLE),
24 Failure to act on the outskirts (‘failure to act’ = FACT) of reality (FACT),
25 Made a great deal of (STRESSED) upside-down (= reversal indicator) desserts (desserts = STRESSED),
26 First person (ELDEST) from Leeds (Leeds = ELDES-) playing (= anagram indicator) the lead (the lead = -T) (ELDEST).
Down:
1 Took one’s time (L-ATE) securing Oxford (-O-) college (-C-) (LOCATE) place (LOCATE),
2 Fired (SHOT) characters from Polish Othello (characters from ‘Polish Othello’ = SHOT),
3 Gifts (PRESENTS) of slippery (= anagram indicator) serpents (serpents = PRESENTS),
4 Polishes off shoe (“polishes” without “shoe” = plis = SLIP) in sink (SLIP),
5 Trim (a) plants (‘flora’ without ‘a’ = FLOR-) with top of implement (top of implement = -I-) that’s new (-N) (FLORIN) from Aruban capital (FLORIN),
6 Soil (DIRT-) next to yard (-Y) helps the flowers grow (WATER) (DIRTY WATER) out of mucky pond (DIRTY WATER),
7 Firm (CO-) plants (flora) deadheaded (f) (“flora” without “f” = -LORA-) for party (-DO) (COLORADO) around Denver (COLORADO),
13 Treats land (treats land = TRANSLATED) contaminated (= anagram indicator) by what the mouthy type did during conversion (TRANSLATED),
14 It’s a type of animal (MA-LE) hanging around top (p) of pine (top of “pine” = -P-) (MAPLE) tree (MAPLE),
16 Steel men (steel men = ELEMENTS) recondition (= anagram indicator) aluminium and silicon (ELEMENTS),
17 Thankful (RELIEVED) it’s about (RE-) piece of fiction (-LIE-) by retiring (= reversal indicator) old leader (Dev = -VED) (RELIEVED),
19 Head barman (attorney general = AG-) gets to open early (open early = -E-) and is the first (1ST = -IST) (AGEIST) to discriminate against those who arrived earlier? (discriminate against those who arrived earlier /those older is AGEIST),
21 Let off (EXCUSE) for Passover? (pass over? = EXCUSE),
23 Idols (GODS) doing the rounds at the Golden Globe Awards (doing the rounds/at both ends of the “Golden Globe Awards” = GODS),
24 Decline (FADE) what’s fancied (FAD-) in the last (e) race (last “race” = -E) (FADE).