When you get down to 9 players form one table. This is the most logical solution. That way chip stack or short stack your odds are evened out. If your players can't make it on time respect the ones that can and have a firm start time with a 10 minutes window where late players are blinded out. Add-ons should be up to and including your first break, after that play what you have. Casual games are great but if you are looking for some structure you need to put some basic rules into place. Your regular players need that respect to ensure they continue to come.
