On a funnier note, the 9 in Falcon 9 is the number of engines. So blue origin is somewhat picking up on their naming scheme. Or, by BO's scheme, it'd be the Falcon 9x1, or the Starship 33x6.
...and we'd be back to steam engine wheel formulas: https://en.wikipedia.org/wiki/Whyte_notation
Ignoring that weaponizing space would backfire badly (you want hundreds of nukes in orbit? yeah actually let's just not do that) and thus no one considering it either.
If you think about that, a lot of fuel for in-space nuclear reactors will already have been launched, so, if a new peace treaty outlaws them, it'll be a boon to whoever operates fission reactors in space. Or wants to use them for propulsion.
Once in space, they can't be disposed of - deorbiting is a big no-no, as it's blowing them up.