I'm probably the last person alive qualified to write a blog post about 9/11. I'm Canadian. I was ten years old on September 11th, 2001, on the opposite coast from New York. The attacks had little to no effect on my everyday life, besides the effect they had on the media.
It took a long time for me to fully understand and appreciate what happened that day. The only thing I can contribute to a discussion about 9/11 is a book recommendation.
If you're like me and spent a lot of years feeling disconnected and unaffected by something a lot of people seem to really care about, read Love is the Higher Law by David Levithan. Besides being a good coming-of-age story with a fledgling romance that makes my stomach flutter, it's a truly transcendent, emotionally telepathic novel. Because of this book, I understand why 9/11 is a big deal. Read it.