Nothing wrong with recommending 9mm, but here in the states, 38 special is still the most common centerfire pistol ammo. I have yet to see any place that sells a selection of different ammunition not carry 38 special, I cannot say the same for 9mm.

It is splitting hairs. I reckon there are darned few places you can go where 9mm is not available, but I have found at least a couple, and in those situations the 38 spec ammo was.

I'd also recommend something much smaller than buckshot as a home defense load alternative. Actually, a blend of different shot size ammo would be ideal. Even #4 buckshot will overpenetrate in a house, picking up unintended secondary targets if you are not careful. A load of #4 field shot is an effective manstopper at household ranges and won't overpenetrate like #4 buckshot does. It still generates about a ton of energy at the muzzle, and at 30-40 feet it won't be much less.