Living on Long Island on 911 many parents pulled their children out of school that morning. While we didn't know what was going on and what was to come I found it safe to keep my children in school instead of having them home dealing with the news. I picked them up that day at regular time and gently told them what had happened and then watched some tv with them and answered their questions.
on 9/11 i did go and get my kids from school as soon as i heard that the Pentagon was hit. At least half of the kids were gone by the time i got there. but i didn't keep them home the following day.
Life is rough and unfortunately kids need to know that. They know that people wanted to kill Americans, so they flew into the Twin Towers, now they also know that there is a lunatic loose in our area that is just shooting people at random. My 8 year old, matter of factly, asked me the other day if we could call daddy because she knew he had to get gas that day and she wanted to make sure he was not shot. i told her that i had spoken to him and that he was fine. Death is a part of life.