i dont think anyone has mentioned this, but once a ball has touched the backboard, it doesnt matter if its still on its way up or down. Its still goal tending according the the ncaa.
In NCAA basketball, WNBA and NBA basketball, goaltending is also called if the ball has already touched the backboard while being above the height of the rim in its flight, regardless of whether it being in an upward or downward flight or whether it is directly above the rim.