A quick rule of thumb, assume action should be over when there are 20 big blinds left. You don't mention how many minutes per blind. But 9 players x 30k (assuming no rebuys) = 270k. So a 20th of that is 13,500. Blind level 36 is 14k. If you have for example 8 minute blinds then over 5 hours. (always count 55 minutes in an hour due to break)