This is definitely a Muslim attack. Supposedly, from what I've heard, the attack was actually scheduled for the previous day, due to it being a Jewish holiday, but for some reason they didn't make it on time, so it just seemed appropriate to do it on a day that matches the national emergency number. However, I can't seem to find proof of this.
Notice that they did it on the first year of a new century, considering that there is no year zero, thus a literal century is the years 1-100 AD, 101-200 AD, etc., and we're in the 2001-2100 AD century. Decades are the same too, though we often do it starting with 0, not 1. In other words, we're doing it wrong.
Yet the Muslims knew this and decided to strike, expecting us in the U.S. to not know what was going to happen. It worked.
They were also testing us. What would we do if we were attacked? They were baiting us, and we fell for it. Bush's Homeland Security was supposed to protect us, but all it has done is restricted the innocent instead of targeting Muslims. To top it all off, Obama allowed Muslims in through our borders, making Homeland Security's purpose useless.
We are a nation in peril, and we don't even know it.