Remember Boxing Out The Free Throw Shooter ...
 

IAABO doesn't deal with rules (he said tongue in cheek).

Education ...
 

I bring this up again, and again if necessary, so that Forum members, especially new Forum members, don't walk away believing that a definite NFHS rule interpretation has been officially stated for this (off the backboard dunk), and similar situations (off the backboard, maybe move feet, catch, maybe start a new dribble). With the exception of the very specific situation (can't call illegal (double) dribble) described in 9.5 SITUATION, everything else boils down to opinions, in some cases informed, rational opinions, but nevertheless, still just opinions.

Of course, the easy way out to this is to just call every such act such as this a try, but we really know that in rare cases it really isn't a try, and it may be readily apparent to an observer (official) that it really isn't a try.

Legal in NBA
 

I asked one of my homeboys who work under NBA rules and he said ...

" Ball just has to hit rim or backboard in order for shooter to retrieve it. Does not need to be a "shot attempt"