I know everyone says wait over night but I personally would give myself the last two hours of light and go look today. That will give him 6 hours.
I agree with this too..... which every place is different but on my place coyotes are the biggest issue.... like 120 stated any pending rain tonight will make any sign tough to follow.
I'd go in at least an hour before dark and try to trail him to the creek you mentioned. Which you described him "hunched" at the shot....and most gut shot critters will head towards water.
But ultimately.... were not there and only you can make the decision on what to do.
Which.... I also say.... hell its gun season in Ky .... take your time and pack a firearm (rifle / shotgun) and finish him off if you jump him up.