UTG bets 18bb

Multi-way River | 3-way: BTN | 100bb effective | Difficulty: Tough

Players in hand: UTG, Hero (BTN), BB

Hero hand

A♣A♦

Board

9♠5♦2♣T♦6♥

Action so far:
River 6♥ on 9♠5♦2♣T♦6♥, pot 24bb
UTG bets 18bb

Pot: 24bb   To call: 18bb

Villain range: UTG three-barrel: AA, TT, sets, AT, Tx, missed AhKh bluffs, 87s

Your move: