Has anyone done the free city tour during a layover in Istanbul with Turkish Airlines?

I have a 9 hour layover in IST next month. I see they offer a free “Touristanbul” bus tour. Is it well organized?

I’m terrified of the bus getting stuck in traffic and missing my connection.

Also, what do you do with your carry-on luggage? Do they keep it on the bus or do I need to store it at the airport?

Thanks!