Weirdly, this tragedy aligned with a rather personal emergency for me, and both events are totally intertwined in my head. I was a freshman in college, and after Labor Day weekend my roommate never returned. Her sister worked for the school and lived in married student housing (she was a graduate student) and my roommate had said she was visiting her sister. I finally looked her sister up in the directory and called her. The morning of 9/11 police entered my dorm room without knocking and took me to the police station. I believe I was a suspect! I was sitting in the station (in my pajamas) when the news flashed on TV. Suddenly this little problem was totally dwarfed. I remember we were at the station for hours because the police basically forgot about me. I didn't give my statement until hours later. A few days later is the annual "See you at the pole" day of prayer, and this was a Christian college: the grounds were PACKED with sobbing students.
Also, my aunt was supposed to be on a flight home to DC that morning and my family was panicked. Turns out her flight was later and already grounded, but this was '01 - she didn't have a cell phone. We didn't find out her welfare until the next day.
P.S. My roommate had run away to Mexico. I dropped the first clue when I was like - you know she's pregnant, right? And her family was like, "NO SHE IS NOT". And then they found very obvious search history that lead them right there. Her boyfriend was supposed to meet her...I do not think that happened. All I know is that I inherited a very nice dorm room all to myself and was told to just shut up about it all.