3/6 88 vs. unknown...too aggressive?

Hi everyone, this is my first post here. I hope I can be a valuable contributor, as I've learned a lot from the forums.

I didn't have much of a read on Villain, as he had only been at the table for one orbit. However, he did get aggressive with a marginal hand a few hands before.

Party Poker 3/6 Hold'em (6 max, 6 handed) FTR converter on zerodivide.cx

Preflop: Heroine is SB with 8[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/diamond.gif[/img]. CO posts a blind of $3.
[color=#666666]2 folds</font>, CO (poster) checks, [color=#666666]1 fold</font>, [color=#CC3333]Heroine raises</font>, [color=#666666]1 fold</font>, CO calls.

Flop: (5 SB) 6[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] [color=#0000FF](2 players)</font>
[color=#CC3333]Heroine bets</font>, [color=#CC3333]CO raises</font>, Heroine calls.

Turn: (4.50 BB) A[img]/images/graemlins/heart.gif[/img] [color=#0000FF](2 players)</font>
Heroine checks, [color=#CC3333]CO bets</font>, [color=#CC3333]Heroine raises</font>, CO calls.

River: (8.50 BB) J[img]/images/graemlins/club.gif[/img] [color=#0000FF](2 players)</font>
[color=#CC3333]Heroine bets</font>....