Are you ready for Thomas (Screaming Comes Across the Sky) Pynchon on the subject of Sept. 11, 2001? On the one hand, his poetry of paranoia and his grasp of history’s surrealist passages make a perfect fit. Yet his slippery insouciance, his relentless japery, risk being tonally at odds with the subject. Either way, and despite his sensibility’s entrenchment in ’60s Californian hippiedom, Pynchon i