I am not a native English speaker. So, sorry for the inconvenience.
But I would like to say that there is a variety of coincidence beteen the date of terrorism and the date of some historical event.
Particularly Japan seems to have something to do with the dates.
For example, September 11 was the day of final surrender for Japan, September 11 has been the day of revenge for some Japanese nationalists.
In New York, they have the same date with Japan only from 5 AM to 10 AM (considering the whole North America). That may be the reason why the terrorist attacks occurred in the morning.
This evidence is just the tip of the iceberg.