The more I think about it, the more I think those news accounts of his location at the time of the first impact are wrong. It is technically possible for him to have been at the hotel at the time of the first impact, and make it to the school by 8:55.

Either that, or Cochran was on hallucinogenic drugs that morning.

I think it's very possible that whomever reported those two conflicting stories of Bush's motorcade location may have been basing their stories on other people's accounts within the motorcade. And the reporters of those stories assumed the President would have learned at that time as well, and reported it as such.