[Unarmed]

Chk/shove is bad, if he bets he's not folding enough.
I'd bet/fold. Either bet normal and shove any river lower than a 9.

or

Bet 100 again and hope to catch him napping/playing showdown poker with crap pair+gutter, then bet big on rivers less than a 9, (to fold out crap one pair hands) big on flush rivers 9 or higher, (he has str8/two pair often) and small on flush rivers 8 or lower. (for val and/or to induce bluff raises with crap made hands)