trip 9s, how is my line

[shant]

Cool. Point taken. I'd add that having not raised the flop, OP made a nice play waiting for the river.

[Songwind]

I like the flop call to avoid chasing the later players out of the hand or inducing the SB to slow down. Since they fold anyway, I am raising this turn.

SB's 3-bet on the river may mean he also has a 9, or may just mean that after your very slow play he doesn't believe YOU have one and he just hit is KJs for Jacks up. I call.