If you were being malicious and didn't intend to kill the intruder, #8 bird is pretty nasty. Going to leave a pretty nasty wound that is hard to fix, what with all the tiny shot going every which way. And if you com'd somebody at about 10 feet while the shot column is more or less still in the wad, that is going to do them no good, probably about a 50% kill probability.
But you can't guarantee a stop. And in home defense you want a stop. Anything from about a 4 and larger your pKill goes way up.
Would I use it? only if I had nothing else and I would follow-up with several shots, I'ld probably go for a blinding shot to the face. Would a leather jacket stop #8 shot, tight shot pattern? probably not, but would keep it from prentrating to any majopr blood vessel, the heart or nervous system component. Get more than about 15 feet and it may stop the shot as it starts to spread.