Against this player I like a river b/f of about 2/3 pot. Fire about $10. If he's suspicious and is hero calling you down you want to make it look like you're trying to make it look scary. You could be beat but not firing three seems like scared play results-orientedness.

On the flop, I'd put his range at any pair, any draw. So 97s suited and even smaller pocket pairs are possible, but I would weight his range towards T9s and Ax with AT-AK being most likely, and you're still ahead of that range. AQ should call all three streets. AT might too.

Strangely enough I had a hand just like this recently where I had AJ and called down three streets after turning top two while villain had AK, but my stats are not so passive.

And since villain is passive-ish, I like the flop and turn sizing.

http://www.pokerstrategy.com
Board: 6h8sAcJc9s
Equity Win Tie
MP2 59.65% 54.39% 5.26% { AsKh }
MP3 40.35% 35.09% 5.26% { JJ+, 88, 66, A9s+, T9s, 97s, 86s, ATo+ }