Most likely it will all fall down to who's technique kills the fastest. Amaterasu is slower and more painful, while bijuu bomb is a quick and near instant death. Don't get me wrong, it takes time to charge, but only a few seconds at that.
Bee shuddered immediately upon contact with Amaterasu and had to perform a tactical retreat instead of annihilate them with a Bijuudama. Doubt the Saiken would use a Bijuudama after Amaterasu is launched.
The bomb would already be charging by the team amaterasu is launched. It isn't instant, as it does take time for the flames to spread and I don't think that Sasuke would start off with amaterasu. Mindset is important as well, remember when he underestimated B? He also overestimated his older brother at this point in time too. Not the best position to be at when fighting an acid spitting chakra demon.
Or Amaterasu would interrupt and impede Hachibi's chakra control which would cause the Bijuudama to disperse as it did with KCM Naruto (initially).
Well in my OP, Sasuke goes after the Saiken INSTEAD of the Hachibi. So Amaterasu would probably not be his first course of action. So basically, can the Saiken kill him before he uses amaterasu? Does amaterasu even kill/subdue?
