All 8 Uses

9/11
in
I Am Malala
(Edited)

We did not realize then that 9/11 would change our world too, and would bring war into our valley.
p. 57.8

9/11 = September 11, 2001; when suicide bombers hijacked US airliners and used them as missiles to kill about 3,000 people
There was really only one subject-9/11.
p. 85.6
Just as the Russian invasion of Afghanistan had changed everything for General Zia, so 9/11 transformed General Musharraf from an international outcast.
p. 85.9
These clerics said 9/11 was revenge on the Americans for what they had been doing to other people around the world, but they ignored the fact that the people in the World Trade Center were innocent and had nothing to do with American policy and that the Holy Quran clearly says it is wrong to kill.
p. 86.6
Khalid Sheikh Mohammad, the mastermind of 9/11, was found in a house just a mile from the army chief's official residence in Rawalpindi.
p. 88.4
Then 9/11 had made this militancy more mainstream.
p. 97.1
The brothers were famed for their fiery sermons and attracted thousands of worshippers, particularly after 9/11.
p. 126.5 *

9/11 = September 11, 2001; when suicide bombers hijacked US airliners and used them as missiles to kill about 3,000 Americans
Before Abbottabad he'd been in Haripur and before that hidden away in our own Swat Valley, where he met Khalid Sheikh Mohammad, the mastermind of 9/11.
p. 212.9

9/11 = September 11, 2001; when suicide bombers hijacked US airliners and used them as missiles to kill about 3,000 people

Definitions:

(1) (9/11)
the terrorist attacks on the United States on September 11, 2001, when hijacked passenger planes were flown into the World Trade Center and the Pentagon, killing nearly 3,000 people

On September 11, 2001, 19 terrorists from the group al-Qaeda hijacked four U.S. passenger airplanes. Two were crashed into the twin towers of the World Trade Center in New York City, causing both towers to collapse. A third plane hit the Pentagon. The fourth plane, crashed into a field in Pennsylvania after passengers fought back. Almost 3,000 people were killed, most of them civilians and first responders. The attacks led to major changes in U.S. security policies and to long wars in Afghanistan and Iraq.
(2) (meaning too rare to warrant focus)
Much less commonly, 9/11 can refer to any September 11th.