9 years is long enough to be "terrified" and remind ourselves of it so we can renew our fears. 9 years is enough repeats of condition orange alerts for an anniversary attack.
I'm particularly revolted with the fact it's the one day of the last year that some people have taken a break from villifying police and firefighters.
If I could I would have memorialized the day by flying without worries to NYC and seeing a show or something. Living without fear that would be an appropriate memorial, a resolve to build a better world to replace the one that was spawned that day.