@Sooner .. all the advice you have been given is great!!! All I can add is to find out exactly what the humane society has covered in their vet check.
As a stray there is a good chance that he had fleas, which gives him a stronger chance of tapeworm. So I would definitely get him tested for parasites. Also, as a stray and then been put in a kennel it increases the chances of him having giardia. Please make sure he is tested for that too. And heartworm of course!!!
Sorry if this comes across as a downer, but being involved in rescue this is the first thing we do when we get a new bully in.
Sooooo .... here's the best part. Somehow it is as if a rescue knows that you have given them their second choice and they return that love over and over and over again.
Thank you for being one of the wonderful people who rescue, and I am almost as excited as you are about his arrival. Is there a date, and time yet????