ACROSS
9 Conservative member to go up (5) 
CLIMB - to go up (def) from C (Conservative) LIMB (member)

10 Change of mind in club game (9) 
BADMINTON - game (def) from DMIN (anagram (change) of MIND in BATON (club)

11 US city starts to limit interference audibly after sound bouncing back is meaningless repetition (9) 

ECHOLALIA - meaningless repetition (def) from LA (US city) LIA (starts to limit interference audibly) after ECHO (sound bouncing back)

12 Apply pressure to alien holding king back (5) 
EXERT - Apply pressure (def) from ET (alien) holding XER (REX=king back)

13 Thus, spies get last of official invites to meetings (7) 
SOCIALS - meetings (def) from SO (Thus) CIA (spies) and last (letter) of officiaL inviteS

15 Better English and European box fasteners (7) 
ECLIPSE - Better (def) from E (English) and E (European) containing (box) CLIPS (fasteners)

17 Force the Spanish to follow a politician (5) 
IMPEL - Force (def) from EL (the Spanish) following IMP (a politician)

18 Strategic intervention required at the start for titled person (3) 
SIR - titled person (def) from first letters (at the start) of Strategic Intervention Required

20 Irate gorgon holds back reference writer (5) 
ROGET - reference writer (def) from IraTE GORgon

22 Novelist King is bad actor (7) 
GRISHAM - Novelist (def) from GR (King) IS HAM (bad actor)

25 One in the know at home with drink, reportedly (7) 
INSIDER - One in the know (def) from IN (at home) SIDER (drink, reportedly)

26 Skirting rumpus, policeman comes around (5) 
DADOS - Skirting (def) from ADO (rumpus) that DS (policeman) comes around

27 Network-like rut Claire repaired (9) 
RETICULAR - Network-like (def) from anagram (repaired) of RUT CLAIRE

30 Spooner's explosive arouser is alcohol producer (9) 
WINEMAKER  - alcohol producer (def) from Spoonerism of MINE (explosive) WAKER (arouser)

31 Vibrators on newspaper heads (5) 
REEDS - Vibrators (def) from RE (on) EDS (newspaper heads)

DOWN
1 Land measure announced by breadmaker with no cap (4) 
ACRE - Land measur (def) from homophone (announced) of (B)AKER (breadmaker with no cap)

2 Drink before settling dark limit (5,3) 
NIGHT CAP - Drink before settling (def) from NIGHT (dark) CAP (limit)

3 A toll shortly for murder victim (4) 
ABEL - murder victim (def) from ABEL (A BEL(L)=a toll shortly)

4 Columns silks rebuilt to order (8) 
OBELISKS - Columns (def) from LISKS (anagram (rebuilt) of SILKS) following (to) OBE (order)

5 Form an opinion of fish swallowed (6) 
IDEATE - Form an opinion (def) from IDE (fish) ATE (swallowed)

6 Warnings upset Lisa Farmer (4,6) 
FIRE ALARMS - Warnings (def) from anagram (upset) of LISA FARMER

7 Actress to look up on street  (6) 
STREEP  - Actress (def) from REEP (PEER to look up) on ST (street)

8 One universal louse (4) 
UNIT - One (def) from U (universal) NIT (louse)

13 Small side to swap partners (5) 
SWING - to swap partners (def) from S (Small) WING (side)

14 Nevertheless, none different (3,3,4) 
ALL THE SAME - Nevertheless (def) none different (def)

16 Salt formed by mixing 7 mostly (5) 
ESTER - Salt (def) from ESTER (anagram (mixing) of STREE(p) (7 mostly)) 

19 Bullies from Republic rest awkardly on side (8) 
ROISTERS - Bullies (def) from ROI (Republic) STER (REST awkardly) on S (side)

21 Fag's lied about annoying wingers (8) 
GADFLIES - annoying wingers (def) from anagram (about) of FAG SLIED

23 Element that is about silence? (6) 
IODINE - Element (def) from IE (that is) about ODIN (zero DIN=no noise=silence) 

24 Gospeller gets car used once for cash in Helsinki(6) 
MARKKA - used once for cash in Helsinki (def) from MARK (Gospeller) gets KA (car)

26 500 have feathers (4) 
DOWN - feathers (def) from D (500) OWN (have)

28 Bother about Fred essentially (4) 
CARE - Bother (def) from CA (about) RE (Fred essentially)

29 Attack heart of scrums and be quiet (4) 
RUSH - Attack (def) from RU (heart of scrums) and SH (be quiet)