I would make it Conjuration just because Illusion is only supposed to be mental and visual effects, and I would make it at Adept or Expert level because teleporting is not a simple feat. This has been said before, but is a definite Immersion breaker. Bethesda has improved the level scaling in some respects, but some things just shouldn't be scaled at all, they should be at fixed levels regardless of the player. Or scaling based on how far in certain quest lines you are, but not on level.