I googled on “.45 9mm stopping power”; not a whole lot of people have confidence in the 9mm apparently.
What if you're not physically capable of handling a .45? What if the gun itself is too big and/or heavy? I have yet to find a .45 that comfortably fits my hand. Trigger reach is always too long, and if I have to strain on my trigger pull I'm not going to be hitting much.
Gosh, am I screwed if I ever get into a life-and-death confrontation in my home?
The answer is an absolute NO. If you find something that you're comfortable shooting, you'll be more likely to practice with it, and if you're more likely to practice with it, then you'll be able to hit what you're aiming at.
The ".45 or nothing" attitude either creates a false sense of security to the person who owns one (or do the makers of .45 ammunition or firearms include some sort of stopping power guarantee of satisfaction that I'm not aware of?) or creates a false sense of inferiority in the person who doesn't own one.
Sometimes the assailants don't give a rat's patootie about the caliber, so you'd better be able to shoot your weapon of choice well, no matter what it is.