Please leave the word "closure" out of your copy.
Closure, in the case of 9/11, doesn't exist. It never will.
Justice is a both a legal and emotional term, what is doled out by courts and what we feel when a wrong is somehow righted. But trading thousands of lives for one doesn't feel like justice.
Relief may be the proper term for this day. For those who lost loved ones, for those who love their country and feel as though it will never be the same, relief may be the proper word. Not because events have magically transported us back to the way things were before 9/11, but because we're a little less afraid that it might happen again.
Nothing can ever bring back those lost on 9/11 and those who fought for freedom in the middle east. So there is no closure for those who lost loved ones. Some measure of justice, and a good deal of relief, maybe.