"always in my thoughts"? Really? You think all the time about the relatives - whom I presume you don't know - of the thousands of people who died nearly six years ago, who I also presume you don't know?
Serious point: of course 9/11 was an appalling atrocity and a tragedy on a huge scale, but that kind of platitude is just nonsense. Unless of course you did know each of the victims and their surviving loved ones personally, in which case I withdraw the remark.