On Monday, 449 students went on a trip to the zoo. All 9 buses were filled and 8 students had to travel in cars. How many students were on each bus?

There were a total of 449 - 8 = <<449-8=441>>441 students on the buses.

So, 441/9 = <<441/9=49>>49 students were on each bus. Answer: \boxed{49}.