Missed draw, continue betting on river?

[WMB]

My brain's not working too good, I need advice on this one. Hand is from a 10-20 live game. Villain is your typical bit too loose, bit too passive, calling station live player. He also seems to be fairly inexperienced at o/8.

So I limp UTG with A234 rainbow and get 2 callers plus the blinds. Five to the flop of A, 5, 9 rainbow. I lead and only the villain who is to my left calls. Turn is another 5 which does not add a 2-flush. I bet again, villain calls. I'm pretty sure he would raise here if he held a 5 or better. River comes a Jack, so I end up with AA554 for high with a 5.5 BB pot. What's the best river play?