When you bet the river you said you were hoping to induce a bluff/shove. As you played the hand, it's probably not a good idea to do this without history, but it is definately a fine move against a player you feel would get bluffy with busted draws. The one thing to keep in mind is if we're betting the river for value, what are we getting value out of. (Although I think you made it clear yourself you weren't betting for value, which is good thinking IMO so there's no need to ask you this question). You might have pot odds to call the river anyway even if he only sometimes bluff/shoves.

Just for the record on the timing tell aspect, I've read about and witnessed players both taking their sweet time on a draw, and also insta-calling, so without any history I don't think we can assume it to be in favour of one way over the other.