I have and still carry both ball and hp.My little lcp usually has ball for penetration and I have had a few hp rounds be slow to chamber or hang up and I have to push the slide forward.
I do not daily carry my 1911 in .45 so I can't comment on that.Some of the short barreled 9mm and .380 pistols...
Can't be sure.I don't have any literature to verify that they did make them but these are visually identical to all of my other BT and it is Winchester brass so I don't know.
While I would rather have a .45 it would depend on how many bad guys and how many bullets the gun held.9mm does have the capacity.
Everyone should at least shoot a .45 once even if they decide not to own one.