I don't think that you had odds on the flop or turn. I would slightly discount your 2 9s there as well as there is a chance you are up agaisnt AA. and the double gut shot should only count as 0.5 outs. Therefore I would count it is 1.75+0.5= 2.25 rounded down to 2.

On the turn you did hit your gut shot, but now you are looking at 3.75 for the gutshot (another diamond would put 3 to a flush ont he board, so slight discount), and the 1.75 for the 9's is 5.5, again, pretty thin.

I don't know about the river fold, I may call this. But then again, I wouldn't have gotten to the point.

I fold this on the flop for 2 reasons:

1 - no odds
2 - SB capped and the odds of a Check/Raise by SB are pretty good.

Margon