Deliberately knocking ball out-of-bounds

I'm a baseball guy and know close to nothing about football rules.

But I was watching one of my son's 7th-grade-football games (high school
rules) and was wondering on the proper ruling in the following case.

The QB is being chased in his own endzone.  He fumbles the ball and it roles
a considerable distance within the endzone and ends up inbounds, but barely
so.  There's a race for the ball.  The offensive player DELIBERATELY knocks
the ball out-of-bounds (in the endzone) by kicking the ball with the clear
intent of preventing the defense from falling on the ball for touchdown.

David Emerling
Memphis, TN