The charge is most probably “grand theft auto”, a 3rd degree felony which is punishable by up to 5 years in State prison. The student will probably not serve a day, but s/he can and should be, at a minimum, punished as an administrative matter vis-a-vis the school board.
As an aside, I don’t expect non-lawyers to be versed in the law, but I do expect public school teachers to be versed in civics. What is more disconcerting to me than a student who disrespects his teacher and breaks the law is a public school teacher who thinks that auto theft is even possibly a federal matter. If you are such a teacher then I truly hope that you teach nothing more intellectual than physical education.
Still, no one deserves to be the victim of crime and if you have not doe so already then you should call the cops – local cops, not the FBI.
Meanwhile, not withstanding my admitted sarcasm, I hope that I have been helpful in answering your question.