I hugely endorse chipping, for a number of reasons.
If your cat goes out and about and is unwittingly taken in by some kindly soul, they will take it to the vets or rescue, whereupon they will be scanned for a chip. If the chip is there the vet or rescue cannot let that person leave with the cat as the cat is legally your property.
If your cat goes out and about, a chip is much safer than a collar, as collars can and do strangle cats when caught on something. It means your cat's address can be found safely and you don't have to pay for new collars every few days (as I had to do at one point!).
In case of an RTA, vets and councils can check for a chip and let you know what has happened, which saves you weeks/months/years of worry, grief and heartache.
Kittens really shouldn't be let out until at least 10 months old, as they are just too kitten-like and are more interested in chasing a leaf than worrying about that oncoming car. Please consider keeping your kitten in until 10 months, and make sure he is neutered and up-to-date with vaccs, worming and flea treatments.
Also, here is a story of how a cat was reunited with her owner, even though the given address on her chip was in Spain!! It does work!!
http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-25997769