also jager even if he has been "3barreling alot" you still need to make a small raise, even a mini raise on this flop because
a) he will push Kx and AA
b) he may push QQ JJ other decent one pair hands putting you on a FD
c) He may push total shit, putting you on a flush draw.

So to maximize your value against all his tendencies a smaller raise on the flop is probably best- and you need to size your raise SPECIFICALLY so that a push by him does not give you odds to call to an 8 or 9 out draw.