Well no matter the history with this guy I don't like your 3bet sizing from the SB with AJo. It's a decent hand 7handed against a player who's on the looser side. Still it's not that easy to play oop in my opinion, so I'd try to take it down pre with something like a 2.3x 3bet if you think he's folding enough. Your 3bet gives him more than 4:1 odds, so he'll flat almost everything like T9s, 22+ etc. You also could just flat and try to play smallball postflop unless you hit good, but the fact that you are oop with a mediumstrength hand would make me prefere reraise imo. You also take control of the hand.

The cbet on a 399r flop isn't bad, I just believe that every good player would float a superdry board like this with any pair, any Ax with backdoor flush/straightdraw and maybe something like JT. Given that I'd just check and see what he does, trying to take it down with a delayed turncbet.

The turn card isn't the best for us, on he other hand you can represent pretty decent here, so I like that 2nd bullet, although I'd make it a little over 1/2 pot to convince him that his best option is folding.

Now that he's called you, I would just give up on the river. Dunno what else you could do here. If you think he's just a weak calling station who might do these three calls with 66 or A3o you can try and make an almost potsize bet.

Probably not the ideal play, just my thoughts on this hand.