Board Thread:General Discussion/@comment-121.219.157.62-20150401050156/@comment-1173941-20150403160358

ALO was a direct copy of a slightly older version of SAO, with some visual changes. This can easily be used to explain why his admin account was in ALO.

We really can't say if the Seed gave him administrative abilities, but I would wager that it's unlikely, considering he created the Seed so that other people could make more worlds, while ALO was just a copied version that already had his account in it.