If a player with Hail Mary Pass catches a bomb, he has no option to use the skill to throw it.
However, rulebook states that:
All skills that may be used when a ball is thrown may be used when a bomb is thrown also.
A bomb may be intercepted or caught using the same rules for catching the ball, in which case the player catching it must throw it again immediately.
There's no distinction between a bomb being initially thrown by a player with Bombardier skill (in which case HMP is currently applicable) and a bomb being thrown after catch/interception.