[Somnius]

1 - His range is huge and 3 nines are already accounted for = greater possibility of Jacks.
2 - His aggression = he would do this with jacks, but since he didn't raise you'd have to take out JT+ from his range.
3 - You underrepresented your hand (common to believe someone would not raise their trips on the flop).

...I'd call here

Against this guy, I would've played it the same to get all in on river...his turn bet also seems weak and Jackish...