I don't believe he made a mod to enable teens to move out on their own, BUT I think you're talking about Inteen that does allow for teens to move out on their own after they reach a certain age in their teen life stages.
You can check
Simbology for updated info about Inteen for Apartment Life. Earlier versions of Inteen are available for FreeTime and older EPs.
By the way, please state your latest expansion pack when you ask us for help so we can find the right mod or solution for you in the future.