Pacific, $0.25/$0.50 Pot Limit Omaha Cash, 6 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite.

SB: $518.76 (1,037.5 bb)
Hero (BB): $50 (100 bb)
UTG: $237.61 (475.2 bb)
MP: $30 (60 bb)
CO: $59.65 (119.3 bb)
BTN: $50 (100 bb)

Preflop: Hero is BB with 9c 9h Kd Js
2 folds, CO raises to $1.43, 2 folds, Hero calls $0.93

Flop: ($3.11) 3s 9d 9s (2 players)
Hero checks, CO bets $1.55, Hero calls $1.55

Turn: ($6.21) As (2 players)
Hero checks, CO bets $3.10, Hero raises to $6.20, CO folds

Results: $12.41 pot ($0.62 rake)
Final Board: 3s 9d 9s As
Hero mucked 9c 9h Kd Js and won $11.79 ($5.71 net)
CO mucked and lost (-$6.08 net)

Basically the question is, what would be the best line to extract max value here? villain is a nit with 29/9 (vpip/pfr) 2 agg, and 3% over almost 6k hands
The logic for the line i took was, that in the flop i dont see any value on betting myself obviously so i let him do, on the turn, since it is an a, and flush completes, i thought that if i donk i might fold out all of his pocket pairs that he couldve bet the flop with jj+, and also his bare pair of aces cos of the spade and he is so very tight. So i check to him to let him bluff(although he rarely does). Since the ace, is suppossed to hit him very hard and pocket aa is heavy in his preflop range, i thought that with a minraise i get calls from flushes and make him shove with aaa99, or make him spazz out if he has something like akkx with a or k of s. Probably i shoulvde just x-c the turn and x the river hoping for him to bet, cos if i bet he's not calling with his weaker hands and he will be betting aa's full anyway. So i guess there is no point on leading vs this specific player.
What are your thoughts?