More explicitly, the 9/11 Commission Report calls it 9:37:46 (Chapter 1, page 10).
In the Larry King interview, Kerry said that they stayed in Daschle's office until they got a call from the White House, saying that it was being evacuated and that's when they evacuated the office. Again, according to the Report, the White House started evacuation at 9:45. So they probably did sit around for 40 or more minutes total.
Kerry says he thinks he called home. No indication when that would be. (first/second/third plane).
Edwards just went home.