Can an Xbox one play on a multiplayer minecraft Xbox 360 world?

I don't think so. There are native versions for each console. If it was only a xbox 360 game made backwards compatible to xbox one, then yes, because it uses the same server for the game to play with both xbox one / 360 players.

but, since there's a native version for each console, i don't think you can.

NO, completely different XBL networks

No. Different versions, different servers, different networks.

No the 360 game is not backwards compatible and that is what you need to play with someone on a 360.

http://www.xbox.com/...able-games