The explanation, from Blue Grass Preps:
Jordan Berry, the EKU punter, took the snap and kicked a rugby style kick to EKU gunner Trey Thomas. Since Thomas was behind the line of scrimmage he was allowed to advance the ball--which he did for a first down. My son is the long snapper and he says that they've practiced this over the two seasons that he's been there but never tried it in a game before.
BUT HOW IS THIS LEGAL?
As noted, as long as the ball doesn't pass the line of scrimmage, the kicking team can advance it. It's a *hack* of the rule that allows the offense to try and salvage a blocked punt or field goal. You know, the rule this high school team took advantage of in order to win a game after having its own kick blocked: