hi, make sure he has been on all your window sills looking out, I read that they can use what they see as a compass to find their way home, let him out gradually building up his territory, short spells leading up to him feeling confident to explore on his own. Before food is a very good idea cyberfyn, one of my cats I started off on a leash, they tend to hug the perimeter first, he may cry, (this is just his flight of fright sensor coming in), it's just to say "hey, I'm not quite sure yet", just short outings at first. Let all your street know you have him, so if he does get lost, they know what they are looking for, & who he bellongs to, you would not believe how many fools just keep a kitten or cat if they see how cute they appear, not thinking of the owner fretting. Also some cats are quite happy having a couple of slaves looking after them, so he may have a couple of homes.
Baloo j. & gentle head butts from fur buddy.