8 Watchmaker, maybe, to show contempt about spring (8) 
JEWELLER - Watchmaker, maybe (def) from JEER (to show contempt) around (about) WELL (spring)

9 Love in outhouse is noble (5) 
BARON - noble (def) from O (live) in BARN (outhouse)

10 Very good unit in pieces (4) 
MEAN - Very good (def - as in "he played a mean game") from A (unit) in MEN (pieces)

11 Car for one by which property is transferred (10) 
CONVEYANCE - Car for one (def) by which property is transferred (def) 

12 A lot of stars happy about Californian airport (6) 
GALAXY - A lot of stars (def) from GAY (happy) around (about) LAX (Californian airport)

14 Least secure feast disrupted following students' revolt (8) 
UNSAFEST - Least secure (def) from AFEST anagram (disrupted) of FEAST after UNS anagram (revolt) of NUS (National Union of Students)

15 Meteor showers blurred on slide (7) 
LEONIDS - Meteor showers (def) from anagram of (blurred) ON SLIDE

17 Coming out of island going to court (7) 
ISSUING - Coming out (def) from IS (island) SUING (going to court)

20 IT company chart is sweet (5,3) 
APPLE PIE - sweet (def) from APPLE (IT company) and PIE (chart)

22 Catch disgruntled parent (6) 
ENTRAP - Catch (def) from anagram of (disgruntled) PARENT

23 Divisions about Conservatives imbibing, for example (10) 
CATEGORIES - Divisions (def) from CA (about) TORIES (Conservatives) containing (imbibing) EG (for example)

24 Rush to father's hotel (4) 
DASH - Rush (def) from DAS (father's) H (hotel)

25 On top of old transporter missing rear end (5) 
EXTRA - On top of (def) from EX (old) TRA(M) (transporter missing rear end)

26 Fruit from bog liquidised in city (8) 
DOGBERRY - Fruit (def) from OGB anagram (liquidised) of BOG in DERRY (city)  

DOWN
1 Do little for Victor, say, visiting English gallery (8) 
VEGETATE - Do little (def) from V (Victor) EG (say) on (visiting) E (English) TATE (gallery)

2 Foreigner’s refusal to corrupt first 4 in 19 (4) 
NEIN - Foreigner’s refusal (def - German for "No") from anagram of (corrupt) NINE (the first 4 letters in nineteen (19))

3 Brave president gets fortunate (6) 
PLUCKY - Brave (def) from P (president) with (gets) LUCKY (fortunate)

4 Brain-box has drunk Inca rum (7) 
CRANIUM - Brain-box (def) from anagram (drunk) of INCA RUM

5 Lady superiors of bachelor live surrounded by twits  (8) 
ABBESSES - Lady superiors (def) from B (bachelor) BE(live) surrounded by ASSES (twits)

7 Conks out on bottom of bunk and criticises (6) 
KNOCKS - criticises (def) from anagram (out) of CONKS on K (bottom of bunk)

13 Agitated nuns lament cancellations (10) 
ANNULMENTS - cancellations (def) from anagram (Agitated) of NUNS LAMENT

16 Ambassador's educational award to Taiwan's leader (8) 
DIPLOMAT - Ambassador (def) from DIPLOMA(educational award) and T (Taiwan's leader)

18 Floating animal shelter (5,3) 
NOAHS ARK - cryptic def

21 Collect fish in temperate centre (6) 
PRAYER - Collect (def) from RAY (fish) in PER (temPERate centre)

22 US sailor supported by umpteen signatures (6) 
ENSIGN - US sailor (def) contined in (supported by) umpteEN SIGNatures

24 Meeting when tide turns (4) 
DIET - Meeting (def) from anagram of (turns) TIDE