Call the river bet with TP?

The CO plays TAG, but we just lost a player and we're 5-handed now.
I 3-bet with AQs and C-bet the flop. Both bets are called.

I show weakness by checking behind at the turn when a 3rd diamond appears, but I don't want to blow up the pot with just top pair and see a free card.

The 9 seems harmless, but the CO bets a big size bet now.

Fold or call?

GG Poker - $0.10 NL (6 max) - Holdem - 5 players
Hand converted by PokerTracker 4

Hero (BTN): 138.3 BB
SB: 187 BB (VPIP: 15.38, PFR: 15.38, 3Bet Preflop: 0.00, Hands: 26)
BB: 101.5 BB (VPIP: 68.42, PFR: 47.37, 3Bet Preflop: 30.00, Hands: 19)
UTG: 207.8 BB (VPIP: 24.19, PFR: 16.13, 3Bet Preflop: 8.00, Hands: 62)
CO: 148.1 BB (VPIP: 21.57, PFR: 17.65, 3Bet Preflop: 9.52, Hands: 52)

SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has Q♥ A♥

fold, CO raises to 2.5 BB, Hero raises to 7.4 BB, fold, fold, CO calls 4.9 BB

Flop: (16.3 BB, 2 players) A♦ K♣ 8♦
CO checks, Hero bets 10.8 BB, CO calls 10.8 BB

Turn: (37.9 BB, 2 players) 6♦
CO checks, Hero checks

River: (37.9 BB, 2 players) 9♥
CO bets 35 BB