I've heard a few alateens speak at Alanon events, in one case a pair of sisters in the 12-14 range and in another a few boys ranging from 10 thru 15 or so. All of them commented about how important it was to be with and communicate with others who understand what its like to have addict and/or raging parents- who won't tease or judge or marginalize them. In one boy's case I've seen a transformation nothing short of magical from a kid who couldn't put a sentence together to one who could speak confidently as part of an alateen panel in front of a room of 50+ Alanons.
I am not involved in Alateen myself, but I stay really tight with Alanon so there is occasional contact through joint events and I know a few Alateen sponsors. I've taken my daughter to some but I don't force her to go.
So I wouldn't propose Alateen in lieu of other work that might be necessary and helpful, OTOH I sure would propose it before putting a troubled kid on meds. The ease & speed with which shrinks start prescribing xanax to children is nothing short of criminal in my view.