Whatever you do, NEUTER
him. Not only will it help in keeping him around, it will ensure that he doesn't contribute to the already overpopulated stray cat population.
And, contrary to popular belief, neutering usually does not make a cat (or dog) lazy. I have a neutered male cat myself that is around 4-5 years old and he still has a frisky streak in him.
Also, if you neuter him young (5-6 months is usually the recommended age), the chances of him spraying in your house are GREATLY reduced!
As for having him be an indoor/outdoor cat, I would suggest doing the introduction to the great outdoors very slowly. Buy him a collar with ID tag (microchipping is a great
option, too, along with the ID tag--if his ID tag were to accidentally fall off, a shelter could still get him back to you if he were microchipped) and a cat harness and take him out on supervised walks at first so he gets familiar with his territory and surroundings.
This slow introduction started at a young age will also help in decreasing the chances of him running away.
Also, since he will be going outdoors, it is very
important to keep ALL his vaccinations up to date (not just the rabies one) and to check him often for fleas and ticks.