Across:
8 Local friend (Bud = BU-D) crossing river (-R-) that is (i.e. = -IE-) (BURIED) submerged (BURIED),
9 First class (first ‘Class’ = C-) to stick (loiter = -LOI-TER) around school (-S-) (CLOISTER) coming from Monastery Walk (CLOISTER),
10 Took advantage of (USED) what’s tied up (= reverse indicator) in trade surplus (in ‘traDE SUrplus’ = desu = USED),
11 Put a name on (IDENTIFIED) one of those singled out (IDENTIFIED),
12 Jaguar (CAR-) cat (-PET) (CARPET) in ground cover (CARPET),
14 Presumably type of locks (PONYTAIL) offering to play in (to play in) loose (= anagram indicator) (to play in = PONYTAIL),
15 8 across (‘buried’ = BURIED) is popular (IN) on reflection (reflection = THOUGHT) (BURIED IN THOUGHT) or engrossed in mind games perhaps (BURIED IN THOUGHT),
18 Little gems (examples of LETTUCES) from rough- (= anagram indicator) -cut steel (cut steel = LETTUCES),
20 Cover old ground (REHASH) with imp from Hampshire (‘imp’ leaving ‘Hampshire’ = hashre = REHASH)
22 Conventions (TRADITIONS) for butcher (= anagram indicator) not diarist (not diarist = TRADITIONS),
24 Emptied a barrel (emptied a barrel/gun = SHOT) of what’s sold in the bar (SHOT),
25 At the end of 15 across (the end of ‘buried in thought’ = THOUGHT-) has sensational summit (‘Sensational’ summit = -S) (THOUGHTS) views (THOUGHTS),
26 Foreign politician (-MP-) meeting writer (-ED-) that is (i.e. = I-E) outside (IMPEDE) bar (IMPEDE).
Down:
1 Going all the way back (= reverse all indicator) in unfinished (d) support (aid) (‘aid’ without ‘d’ = -IA) boat (-SS-) to old city (UR = RU-) (RUSSIA) state (RUSSIA),
2 Little stint (Little Stint = BIRD) in brambling? (Brambling Finch = BIRD),
3 Made a scene (A-CTED) over theologian (Doctor of Divinity = -DD-) contacting one (-I-) (ADDICTED) caught in the habit? (ADDICTED),
4 Hotshot (ace = AC-E) ringing hospital (-H-) (ACHE) in distress (ACHE),
5 Attorneys having no say (‘attorneys’ having no ‘say’ = ttorne = ROTTEN) in what’s dishonest (ROTTEN),
6 Someone who is easily manipulated (A SOFT TOUCH) by answer (A-) from Silken (silken = SOFT) Thomas, initially (‘Thomas’ initially T-), and that hurts (-OUCH) (A SOFT TOUCH),
7 I’ve fresh (I’ve fresh) soup (= anagram indicator) (I’ve fresh = FEVERISH) and it’s hot! (FEVERISH),
13 Worked on The Wall (POINTED the wall) to expose (OUT) (POINTED OUT) what the commentator did (made a comment /POINTED OUT),
14 Listen up – failing to get lie (‘listen up’ – failing to get ‘lie’ = stnup = PUNTS) of long, narrow flat-bottomed boats (PUNTS),
16 Exposes (UNEARTHS) setting (= anagram indicator) sun (sun = UN-S) going around our planet (-EARTH-) (UNEARTHS),
17 Musical instrument (harp = HAR-P) consuming one of those in The Police (Detective Sergeant = -DS-) on successful song (hit) briefly (t) (‘hit’ without ‘t’ = -HI-) (HARDSHIP) produced by Dire Straits (HARDSHIP),
19 From what’s been heard you won’t forget this (CATCHY tune) is caught (music key C-) from yacht (yacht) at sea (= anagram indicator) (yacht = -ATCHY) (CATCHY),
21 Is likely to avoid the spotlight (SH-Y) over weird type (-ODD-) (SHODDY) Jerry built (jerry-built = SHODDY),
23 Drive out (OUST) of south-east without haste (‘south east’ without ‘haste’ = sout = OUST),
24 Tests the water (SIPS) and current (-I-) for midshipman (mid ‘shiPman’ = -P-) in boat (S-S) (SIPS).