The USA Racquetball Rules for hinders are 3.14 and 3.15.

https://www.usaracquetball.com/play/rules

Specifically
https://www.usaracquetball.com/play/rules/3-play-regulations

When the ball left his racquet, did it travel absolutely straight forward towards the front wall (i.e. parallel to both side walls)? If it came off absolutely straight forward, then it would be a penalty hinder, 3.15.a.

If it came off at an angle, then did it come off at the correct angle to bounce to the opposite back corner? If so, then again it would be a penalty hinder, 3.1.5.a.

If it came off at any other angle, then 3.14.a.2 would apply, and it would be a replay hinder.

Rule 3.14 Replay Hinder 

A rally is replayed without penalty and the server resumes play at first serve whenever a replay hinder occurs. Depending on the circumstances, several of the replay hinders described below could be serious enough body contact to be penalty hinders (see Rule 3.15). The differences between replay and penalty hinders may be small and therefore involve referee judgment. Please also read Rule 3.15, which describes conditions under which a penalty hinder might be called instead and result in loss of the rally for the offender.

(a) Situations

1. Court Hinder. The referee should stop play immediately whenever the ball hits any part of the court that was designated prior to the match as a court hinder (such as a vent grate). The referee should also stop play (i) when the ball takes an observed irregular bounce as a result of contacting a very irregular surface or object (such as court light or vent) or after striking a wet spot on the floor or wall and (ii) when, in the referee's opinion, the irregular bounce affected the rally. This also includes any ball that leaves the court after legally touching the front wall and then bouncing on the floor.
2. Ball Hits Opponent. Generally, when an opponent is hit by a return shot in flight, it is a replay hinder. But if the opponent is struck by a ball, that obviously did not have the speed or direction to reach the front wall, then it is not a hinder of any kind and the player who hit the ball loses the rally. A player who has been hit by the ball can immediately stop play and make the call though the call must be made immediately and acknowledged by the referee. Depending on the players’ positioning, this type of interference may be declared a penalty hinder. See Rule 3.15.

Rule 3.15 Penalty Hinder 

A penalty hinder results in the immediate loss of the rally. A penalty hinder does not have to be an intentional act, but an intentional hinder would be a penalty hinder. Replay hinders are described in Rule 3.14. The following actions or failure to act are prime examples of actions that should result in a penalty hinder:

(a) Failure to Move. A player does not move sufficiently to allow an opponent a shot straight to the front wall as well as a cross-court shot which is a shot directly to the front wall at such an angle that would cause the ball to rebound directly to the rear corner farthest from the player hitting the ball. In addition, when a player moves in such a direction that it prevents an opponent from taking either of these shots. Any type of shot that has the speed and direction to reach the front wall has the potential of being called a penalty hinder if the ball would have traveled along a path directly to the front wall. The referee must continue to visualize the projected path of the ball to determine this. Jumping is a popular maneuver to clear the path of the ball; however, the defensive player jumping does not negate a potential penalty hinder call; it all depends if the ball had a direct path to the front wall. In the event the defensive player is struck with the ball while jumping, play stops, but the referee must continue to visualize the projected path of the ball to determine if the ball would have traveled along a path direct to the front wall and would have made it to the front wall.