“Fahrenheit 9/11” opens tomorrow, and one celeb has already weighed in with an unofficial rave. A source was sitting behind Demi Moore and Ashton Kutcher at the Hollywood premiere and says that Moore was “really, really vocal” throughout the Bush-bashing documentary. “She was hollering and cheering at the screen and yelling things at Bush,” says the source. “And she was pumping the air with her fist and saying things like, ‘That was really harsh' and ‘That was really crucial.’ ”