After being shot in the house through both my knees by a 9mm, I prefer 5.56 for home defense.
9mm will ventilate you, but you might not even feel it and can still fight/kill. I didn’t even go into shock and I had 4 drinking fountain faucets bleeding like a cartoon from my legs/knees.
You will probably know when you’re hit with 5.56.
I still think he deserves a promotion to SSGT or something like that, if he was in.
But I read is autobiography. Not really into that and it really was self defense.
Anyway, to the question at hand.
Most ready and mobile is my 9 mm with the 17 rd mag, one in the pipe. I have the booger picker safety.
The most accurate, of course, would be the 5.56 because you have three points of contact. Trigger hand on the grip, butt on the shoulder, off-hand on the handguard. That's why even grandma can do great with a 5.56.
Shotties are nice, to0, but perhaps a bit awkward in tight spaces. Mine is a Mossberg 590A1 SPX and it holds 8 of the 2.75" shells in the tube and one in the chamber. And it came with a bayonette, as well. Smooth bore, it does well with slugs, which make giant holes that do not stop bleeding.
But for now, my S&W M&P M2.0 in 9 mm with the 4.25 barrel and the 17 rd mag is the best bet. Agile, easy to handle, accurate for what I need from it. Never far from me, usually on my person in an OSB holster under a large shirt, sweater, or jacket.