"Let's meet at 9."
It's rude to be late, it's really rude to not at least call the person when you both have cell phones and let them know you are running behind and give a better estimate of time.
I cannot stand people who are chronically late. Occasional is understandable, things do happen. Of course, there are always excuses like traffic, getting gas, etc. but why not leave a few minutes early? If it takes 30 minutes to get somewhere, then allow yourself 40 minutes, not 25, for the trip.
Some people just think they are above arriving on time. They like to make a grand entrance and make themselves sound so important with their busy excuses. They want to believe the world stops for their gift of appearance.
What to do when it is 9:30 and you are still waiting for The Gifted One's Appearance?
Leave. Jot a quick note, "Sorry I couldn't wait anymore. Maybe some other time." and give it to a member of the waitstaff or a clerk.
Be prepared for an attempt for the blame to be passed onto you, but don't fall for it. Nip it in the bud with a pleasant comment like, "You were running so far behind, I was afraid our meeting would just add to your delays for the rest of the day. Why don't we reschedule for a day you have more time?"
You don't have to put up with it if you don't want to, but you don't have to be rude in getting your message out either. Encouragement brings more positive change, but tension and insults end friendships.