Villain has folded to almost every 4-bet he's faced. I think his range here for flatting is hence pretty strong and probably comprised of value range he isn't willing to get in like 99-JJ maybe and AQ perhaps KQs AJs. I also wouldn't fully discount QQ+. I decide to just give up post flop vs this range. River is a great card for my range and not very good for his which I expect to be comprised of AQ AJ kind of stuff by now, maybe sometimes the odd 99/TT that didn't lead the turn.

PokerStars - $1 NL (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4

SB: 146.23 BB (VPIP: 23.92, PFR: 20.14, 3Bet Preflop: 7.64, Hands: 733)
BB: 151.7 BB (VPIP: 25.78, PFR: 18.13, 3Bet Preflop: 8.89, Hands: 362)
UTG: 133.45 BB (VPIP: 13.39, PFR: 11.81, 3Bet Preflop: 6.38, Hands: 131)
MP: 116.38 BB (VPIP: 12.50, PFR: 7.50, 3Bet Preflop: 6.25, Hands: 84)
CO: 100 BB (VPIP: 25.27, PFR: 21.64, 3Bet Preflop: 5.47, Hands: 567)
Hero (BTN): 186.63 BB

SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has 5 A

fold, fold, fold, Hero raises to 2 BB, SB raises to 8 BB, fold, Hero raises to 20.4 BB, SB calls 12.4 BB

Flop: (41.8 BB, 2 players) 9 6 9
SB checks, Hero checks

Turn: (41.8 BB, 2 players) 2
SB checks, Hero checks

River: (41.8 BB, 2 players) K
SB checks, Hero?