I wouldn't look to a historical date
I don't think the fact has been sufficiently stressed
these people were practitioners of some occult rite
(not exactly a new thing in the history of Islam)
I wish I had listened to that Bin Laden tape more carefully
there were quite a few references to dreams,
it is clear that dreams play a great role in their 'strategy'.
And that weird last testimony of Atta,
(shaving the body, etc.)
is it available somewhere on the web??
Are you thinking of the Arabic documents that were left behind by several of the hijackers (the various copies are quite similar)? The copy I've seen refers to: "Depleting the excess hair from the body and perfuming".
See this link. It includes both an English translation of one of these documents and an analysis of that document. The analysis makes it look even stranger than one's first impression. Here are photographs of one of these documents.
I don't think it's correct to describe this as a suicide note or as Atta's last testimony though (read the analysis in that first link). Or maybe there's another document you're thinking of?