I don't recall the manga saying that the biju would actually die with their host, I think people misinterpreted it as that.
The line I'm talking about is when kushina says "If I drag the Kyubi down with me and die, it will delay his resurrection." I don't think that line means the Kyubi will die and come back, I think that means she will trap the Kyubi within her and after a certain amount of time, he will be able to escape again.
So I guess what I'm saying is that the 'resurrection' is not an actual revival of the dead biju, but the biju coming back into the real world, after having been trapped within a Jinchurrinki. I don't think the Biju's can actually die, only be sealed away for a time.
Anyway, in regard to him rescuing Naruto, the best answer I've ever heard to this problem is that a Biju may be forced to endure a massive amount of suffering inside the body of a dead host. Basically what I've heard from others is that perhaps the process of their host dieing is quite painful for them somehow and perhaps they have to endure a lot before they can actually get back into the real world.
We know that a person's mind still shows activity a decent amount of time after death. So perhaps the bond with the Jin stays active for a while? But perhaps the jin being dead causes the Biju suffering and a great deal of pain. So its possible that the amount of pain he'd have to suffer was not worth it to him, and he wanted to let Naruto live.
He did say that Sasuke would regret killing Naruto, so perhaps he intended to kill Sasuke after being freed because he'd want Sasuke to pay for making him suffer that pain.
