However I notice the poster talks about 9AM meetings. In every company I've worked for, there are people who have a habit of scheduling meetings at the very beginning of the working day, at 8 or 9AM. There are also programmers who have a habit of coming in later, at 10 or 11AM, which is fine except the days when there are meetings.
You can write and complain and admonish and discipline, but sooner or later you have to realize scheduling meetings first thing in the morning doesn't work for non-morning people. They will always be late, or slow, tired, and out of it. If you notice that about 1/3 of your staff never makes the 8AM meeting on time, it's the meeting time and not the staff that's the problem.
Also, making meetings very long and irrelevant encourages tardiness. You've decided to waste my time by making me go to a big group meeting where two people are going to argue about something that does not impact my work. Fine, but don't expect me to make an extra effort to rush to it. I can get some of my time back by being late.