While I understand your reaction from reading the warnings given to first time keepers, those warnings are only given to minimize any issues we have control over. The truth is these animals can deal with stress and are not tubes of glass that will break if you look at them wrong. If he was going to throw up it would've been right then or soon after, you have nothing to worry about. I wouldn't think twice about moving my snakes around even if they ate 5 minutes ago. I'm just not going to have a recreational handling session or take them to an expo until they have had some time.
I remember feeding an animal I just got the week before, instantly took frozen from me without issue. Come back 20 minutes later to make sure she ate it, I notice mites on her. Don't think I was waiting any amount of time to put her in a freshly PAM'd cage. She was fine.