Valedictorian only matters in High School; maybe College, but not quite nearly as likely, since College/Uni is all about specialization, not childhood friendships/rivalry.

1) A scandal is a scandal. Just pick up the pieces and move on. Dwell any more, and it's going to haunt you.

2) Depends on your angle. Also viable if you care only about revenge and not status, and would rather stick it to the person, all nice and personal. If you have to prove that you're smarter than someone, it isn't worth your time.

3) Does it matter? 8th grade means absolutely nothing, and you shouldn't even consider it to be anything.