Weird river spot, when we block bet and get raised huge

A little info on the villain and game flow.

Villain sat w 1k. Drinking. Loud, having a good time. Adds 1k more, within the hour he’s down to 1k. Game is playing pretty loose.

Avg stack at the table was approx 2.5k

1/3 NLH, match the stack, 7 handed
1k effective.

Preflop:
UTG straddle 6. UTG+1 blind raise to 12. Folds to us in the sb, we have 9h9s, we raise to 40. Folds to the blind raiser and he 3! To 150. We call.

Flop (pot 300):
Action: 8h 7h 3d. We check. Villain bets 100. We call.

Turn (pot 500): 3s
Action: check/check

River (pot 500): 3h
Action: We block bet 75 ( targeting A high, the occasional K high)

Villain raises to 500. Us?