Yes....but no.
I'm not counting on the round makin' 'em fall over. I AM saying, however, that the larger the round, the more ya git their attention. Jest like shootin' a bear with a .380 vs. a 7mm mag. Both might kill 'em - but which one will YOU wanna shoot 'em with?
Neither. 375 H&H suites me
But you make an excellent point. Shot placement is important, but given a 9mm vs a .40 that can be shot equally as well... give me the .40. It comes down to what ever you carry or use for home defense, make sure you can hit where you aim. If you simply can't shot the .40 well you might be better off with a 9mm. And given today's fine defense ammo, you're in pretty good shape with a well placed 9mm with something like a HST, or +P Gold Dot.