ACROSS
 7. <be fanatically invested> OBSESS = (.r)OBS ESS(e.)
 8. <sport> HOCKEY = HOCK + _E _Y
 9. <you've done well> ATTAGIRL = AT TAG IRL
10. <tiny insect> MITE = "MIGHT"
11. RAINED after UNREST = UNRESTRAINED <without moderation>
14. (CALM MEDIATOR)* = MELODRAMATIC <overemotional>
17. <location> SPOT = ←TOPS←
19. <fireproof material> ASBESTOS = BEST inside ASOS
21. Z_C inside MEAL = MEZCAL <drink>
22. SOLDIER - I_ = SOLDER <alloy>

DOWN
 1. A BST RUSE = ABSTRUSE <hard to understand>
 2. <fix> REPAIR = R_ + EP AIR
 3. A + STI = ASTI <somewhere in Piedmont>
 4. + P_, HILT RUM = PHILTRUM <part of one's "stiff upper lip"?>
 5. <seafood> SCAMPI = SCAM + PI
 6. H + EAT = HEAT <warmth>
12. ←IRE'S← + ALLY = SERIALLY <in a row>
13. <included> ENCLOSED = CLOSE inside END
15. <public perception> OPTICS = OP + TICS
16. (LETS US)* = TUSSLE <fight>
18. PIE _R = PIER <seaside attraction>
20. BA'S + H = BASH <party>