river value bet?

[Getliquid]

Villian is 35/9 over 90 hands. Hes not very good. Seems to underbet/slowplay big hands.
Heros image is TAG.

Party Poker No-Limit Hold'em, $ BB (6 max, 5 handed) FTR converter on zerodivide.cx

Hero ($165.39)
Button ($198.86)
SB ($85)
BB ($154.05)
UTG ($100.10)

Preflop: Hero is MP with A[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/spade.gif[/img]. SB posts a blind of $0.50.
[color=#666666]1 fold</font>, [color=#CC3333]Hero raises to $4</font>, [color=#666666]1 fold</font>, SB (poster) calls $3.50, BB calls $3.

Flop: ($12) 6[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] [color=#0000FF](3 players)</font>
SB checks, [color=#CC3333]BB bets $2</font>, [color=#CC3333]Hero raises to $12</font>, SB folds, BB calls $10.

Turn: ($36) 4[img]/images/graemlins/club.gif[/img] [color=#0000FF](2 players)</font>
BB checks, [color=#CC3333]Hero bets $24</font>, BB calls $24.

River: ($84) 5[img]/images/graemlins/club.gif[/img] [color=#0000FF](2 players)</font>
BB checks, [color=#CC3333]Hero bets $70</font>

bet river looking for max value from ak/kq? how much?
or check behind figuring villian has nothing (flush draw) or is winning with slowplayed set/78s/weird 2pair?
thx