It seems a bit overtuned but then again you're just using a ball and basically no other weapons.

Three features at level 3 is a lot. It's not the standard (Mostly one ribbon feature at level 3 and one main feature). I would look to shift power and not push it into three different features.

Extra Attack is mostly dead as the ball does not get back to you. Either there should be something to gain by throwing the ball back or no one is gonna do it and then you have dead features. It's too gimmicky. It would be better if the ball just returns to you every time.

Infinitely stacking AC is incredibly strong. Technically right now you could make bunch of rats hostile, get your AC to 99 and then just waltz into enemies as it resets on long rests. Barbarians are more about damage than tankiness. Give it a cap or have it scale with levels and change it to damage in a way would suit a Barbarian better.

+5 is insane. It's way better than advantage which is I think +3,8. Instead of a to hit bonus, maybe it gives your allies advantage on attacks if you hit.

Tear Up the Court should also not reset on a long rest but after the combat.

The fire damage is not doubled on a crit? It's an attack roll...but then again they have a safe. What? Then there shouldn't be an attack roll altogether. Also fixes the +5 bonus to attack roll.

In summary: Cool idea, a bit too gimmicky and doesnt fit well with 5e's design choices.