99 overpair vs turn push from maniac

[HarryPoker]

Vilain is 90/50/1.67 over 50 hands. he looks really like a donkey and has a huge stack... I just saw him call an all-in bet with King high and no draw. Even though I know this is different since he went all-in, I'm pretty confident in my read and thought about calling. I put him on pretty much anything (draw, an 8, air).
Comments on all streets appreciated.



Titan Poker 0.10/0.20, hand converted by the iPoker Converter at Talking-Poker

Button ($72.63)
SB ($19.80)
BB ($20.38)
UTG ($10.30)
UTG+1 ($36.83)
CO Hero ($21.63)

Preflop: Hero is in the CO with 9c 9h
UTG calls 0.20, 1 fold, Hero raises to 1.00, Button calls 1.00, 3 folds.

Flop (2.50) 8d 4c 6s
Hero bets 2.20, Button calls 2.20.

Turn (6.90) 3d
Hero bets 5.00, Button moves all-in for 69.43, Hero ????????