Hi I think all the answers given are the right ones, but you have to choose which one is right for you. Some people are dead set against keeping cats indoors, others feel that it is fine as long as they are kept busy with plenty of toys and scratching posts etc. I have two cats and do let them go out, but I worry like mad if they are not back in at their 'usual' time. They always turn up though, like bad pennies!
Just a couple of things to think about , if you do decide to let your kitty out. What about other cats in the area? Some can be quite territorial and it could be likely that he may get into a couple of scraps with other cats who don't want to share their territory. My vet advised me to ensure that my cats were big enough to look after themselves, but at 8 months I expect sure yours will be fine. Also, I may be stating the obvious, but ensure that he is fully vaccinated and protected from any nasties lurking out there.
Finally don't think that he is just waiting for his chance to make a dash for freedom! He is probably simply desperate to get out and explore the surroundings a bit.
You sound like a loving cat owner and I am sure, like most cats, he will want to come back to some good grub and plenty of attention! Best of luck, Sue