ACROSS
 1. <performer> DRAG QUEEN = Q inside DUNGAREE*
 6. <administrator> SYSOP = S ←POSY←
 9. <construction> EDIFICE = (.t)ED IF I CE(r.)
10. (BELT RUM)* = TUMBLER <glass>
11. <member of Murphy's tribe> BLACK NIGHTSHADE = AC KNIGHT'S H inside BLADE
12. COAT + I_ = COATI <American mammal>
13. <aid for organising> INDEX CARD = IN DEAR D outside XC
15. ←NAME TUN + I'M← = MINUTEMAN <ballistic weapon>
17. <prize> AWARD = A WAD outside R
19. AIRED A LET IE R_ outside ERR = AIREDALE TERRIER <dog>
22. ACHE AN outside A = ACHAEAN <Homeric Greek>
23. BRA V + ADO = BRAVADO <bluster>
24. <bone> TALUS = LUST* outside A

DOWN
 1. <brainy misfit> DWEEB = DEB outside WE
 2. <he said sesame> ALI BABA = A_ L_ I_ B_ A_ B_ A_
 3. (QUINTETS + WICKED)* S = QUICK-WITTEDNESS <acumen>
 4. (.n)E REMIT IS M(o.) = EREMITISM <practice of devoted solitude>
 5. <score> NOTCH = NOT + C H
 6. <&cd> SAME-SEX MARRIAGE {when e.g. two men's "I do"s bind them together legally}
 7. <fruit> SULTANA = (NUT SALA_)*
 8. ENDED after PORT = PORTENDED <forecast>
12. COMB ANT outside AT = COMBATANT <fighter>
14. <Bedfordshire town> DUNSTABLE = _D UNSTABLE
16. <swimmer> NARWHAL = ←RAN← + W + HAL
18. (TIO + A MAN)* = ANIMATO <vigorously>
20. <provides URL for> LINKS <drivers' course>
21. <French runner> RHONE = (N E) after RHO