That is not a vehicle, that is a pet battle. Not the same.
It is currently not possible to hide ForteXorcist in pet battle.
If you took the effort to use a search engine (e.g. Google) you'd find first hit the issue is known. Ticket is here. Further suggestion by me suggested the author of ForteXorcist is busy with other stuff but plans to update ForteXorcist for MoP. So the bug remains for now. Actually, in a way it is useful to see due to world PvP.