It was a good move on your part....you had multiple outs and a flopped straight. Occasionally someone is gonna have 9/10, thats just the way of things. It would be lower variance for you if you were to throw out a feeler bet and try to narrow down possible hand ranges and you could also try to peel off a card or two more to see what could possibly beat you.....That's a low variance play but it might also bring your +EV down in that situation over the long run.