Free throw violation- shooter

[ChrisP]

I am new to the officiating world, I would appreciate your input. I have a question as to a legal attempt by the free throw shooter.

It has been my understanding that to be a legal attempt on the part of the free throw shooter, the feet must remain behind the free throw line, until the ball has made contact with the rim or went through the rim. I have another official telling me that as long as the feet are behind the free throw line prior to the ball being released that it is a legal attempt. Rules 9-1 and 9-3-e seem to be the relevant rules, but they do not address the location of the ball. Thanks for the input!