[jearef]

Sitch 1. No violation, due to specific exception set forth in Rule 9-9-3.

Sitch 2. Jump ball ends when ball strikes the floor, so 9-9-3 exception no longer applies. When A3 jumps from the frontcourt and secures the ball in the air, we now have Team A in control of a ball which is located in the frontcourt. When A3 lands in the backcourt, we have a violation.

Sitch 3. Ball striking the official is the same as touching the court at the official's location. Jump ball ends when the ball strikes the floor. A3 jumps from the frontcourt and secures the ball in the air, giving Team A control of a ball located in its frontcourt. When A3 lands in the backcourt, he violates.

Sitch 4. No violation, due to specific exception set forth in Rule 9-9-3.

Location of the ball and team/player control are pretty basic rules concepts.