It's almost cliched to -- when speaking about 9/11 -- to say, "the 9/11 attacks."
Calling them by this rubric colors the discussion with the US government's spin on that day's tragedy.
What I'd recommend is a more neutral term. When speaking about that day 8 years ago, I'd suggest "the 9/11 events."
Such a term encompasses the events in New York and Washington, but recognizes that there were all kinds of anomalous happenings that day that are still unexplained: the crash of the airliner in Pennsylvania, the fall of WTC 7 that afternoon, the stand-down of the US defenses that morning, and the unexplained options trades in the stock markets in the weeks prior to 9/11, among other things.
History is important. This is an event which I think will be remembered a thousand years from now, and it should be described in ways that encompass all of what happened that day, and in the days prior.