In the U.S. it's completely legal in most states to purchase armored vehicles. Most people can't afford them since even used decade old vehicles are $300k+ . This is very similar to why it's 100% legal to purchase soft body armor even level 4 (resistant to armor piercing rifle rounds) plates. Personally, banning items like this seems backwards, since politicians and rich people can afford to hire dozens of people with assault weapons and body armor while common folk can't.

Also, claiming something is "resistant to 9mm" doesn't really mean "bullet proof". A lot of things are inherently impervious to pistol rounds, I can just about grantee 7.62x39 or 5.56x45 would sail right through the cybertruck.