What age safe to change to clumping litter?

It was soon after I got Gizmo I was told to stay away from clumping litter for a kitten as they can play and swallow it and cause issues.  The stories seemed anecdotal but I decided not to take any chances and went with a clay non-clumping litter.  He's 8 months old now and I was wondering if it's definitely safe by now to switch over to the same litter I use for our older cat. 

It isn't anecdotal at all.  Kittens are very inquisitive and at the beginning of litter box training apt to play with the litter more than eliminate in it.  Also, test it out to see if it's edible.

Last I read, any kitten over 4 months is good to go with any other litter you choose.  By that age they have made the connection that litter isn't food.  So you boy is more than old enough to switch over.  

Eating litter happens around the time the are weaning. I use swheat scoop which is a naturally clumping wheat litter that breaks down when digested until ther ten to twelve weeks old. Then i switch to my regular litter. I havent ever seen a kitten over 8 weeks eat litter but i suppose its possible.

I have always used sawdust it's 100% safe and ive never had a problem plus it leave a nice odour all the time