Bet the flop bigger since so much stuff will peel at least one street Qx/Jx/diamonds/straight draws and gutters.

He can't be bluffing with much on the river because fish like this won't usually turn Jx/T9 into a bluff and QT/JT/diamonds/98cc etc etc all got there and don't want you to check back.

edit to say I agree with JKDS