At what level did Xabi Alonso play Gaelic football?

Xabi Alonso is the only person to have both a Champions League medal and an All-Ireland medal.

I was told this wonderful bit of trivia, and would like to confirm it before using it in a quiz I’m writing, but am having difficulty doing so. He certainly has a Champions League medal, and he certainly did spend some time in Ireland in his youth (on a school exchange programme to improve his English), and did play some Gaelic football while here.

However, some sources say he just joined some local lads for an occasional kickabout, while others say he was in Ireland long enough to actually join a team properly, and some say that the team won an All Ireland final (one said it was a school team; another said it was not affiliated with a school and was just the underage team from Kells, Co. Meath). Most of this is just speculation on various messageboards. Is there any actual record of this?

(I suppose a supplemental question would be whether anyone else has both medals, but we’ll save that for a separate question.)