I don't think that 8 is too young, if the young man's keen to get started, by all means get him started! But I would suggest that you research the teachers, because the right one will inspire him to continue at it, and the wrong one will quickly kill all the joy.
There is a young man in our neighborhood whose family has very little resource. The first time he saw my fiddle, he gravitated to it like a catfish rising to dough bait. I spoke with his parents about his mucical interest. "We can't afford and instrument, and we can't afford lessons," is what I was told. A few weeks later, I was going through a second hand store. There was a 3/4 fiddle Just the young man's size. I asked his parents if it would be all right for me to buy it for him as a Christmas gift. They said that would be great. That young man has been coming for a weekly lesson since, and has made remarkable progress. I make the effort to keep the lessons fun. His grades went up in school; and he's gotten more responsible about his chores at home.
A fiddle and a little personal interest on my part have made all the difference, and I'm grateful. I haven't taken a dime for the lessons, but believe me, the reward of seeing this young man strive has been ample compensation enough!
Hardiman the Fiddler