Osama's Test Score

Okay, so you're a simple bear who needs this explained. The joke uses a pun. '9/11' sounds like a score you might get on a test, like getting 9 out of 11 correct answers. But, you know, '9/11' is also the date of the terrorist attacks that Osama bin Laden planned. The joke is dark because it's mixing a terrible historical event with a silly test score. You probably think this is funny, which is fine, but you're still not as smart as me.