can we call this riveR?

[overAchiever]

I would not call, especialy since his stats are pretty passive so far. The most probable holdings I suppose on the flop for him would be a pocket pair smaller then a 9 on the flop or a flush draw or a 9 with a worse/better kicker. I guess sets or higher pocket pairs are also pretty slightly possible.

The flush gets there on the turn and if he did have 88 77 66 etc then him betting on the river doesn't make a ton of sense given his style since he has atleast some showdown value. I don't think you ahead often enough here to make this a good call, can't see many hands in his range you are ahead of and I am not sure he bluffs in this spot (though I know the sample of hands is small) ...