In football is a center sneak legal?

Answer 1

There was a lot of confusion in the answers, so here's some rules I've interpreted from the NFHS rules:

A legal snap must leave the centers hands and either handed directly to the qb in a clean manner (if the QB is under center) or in the direction of a player in a position in the backfield to receive the snap (shotgun/pistol/etc...), otherwise you have an illegal snap (same as a false start).

A forward handoff IS possible and IS legal (though it does have consequences, like it is considered a forward pass when considering a second pass for illegal forward pass violations), but to forward handoff to any offensive lineman, the lineman must first turn around, square his shoulders, and face his own endzone. After he does that, he may receive a forward handoff.

A lineman can take a backward handoff at any time.

So with those rules in place, there is no way you can 'center sneak' in any level of football. The closest you can come is to backward handoff to a pulling guard, or something like that.