I think you have them mixed up with the Scots....I have many friends in Ireland and I don't think, although the Irish did wear kilts, that it is deemed traditional dress! My old manager from Edinburgh....Now he loves any opportunity to put on the kilt and sporran and sgian dubh.
I was told by a few people when I was in Ireland that some schools have the kids wear kilts.... I don't know. That is just what I was told and I have a photo in a book (photo book of Ireland) of some school kids in kilts as well. I don't know. Maybe it is a special occassion thing?