Try the journey yourself at rush hour, make sure you are carrying both a rucksack with a couple of books in it and a PE bag with a full football kit.
When it gets busy give up a seat for an adult.
Then consider train strikes, if the train isn't running how will he get there, ditto bus.
Then the cost of travel, I know in some areas children travel free but not in all areas.
Does he lose things? It's much harder to find a planner that has been left at school than a planner that might have been lost at school, on a train, on a bus or on the street.
One of the things I hated was that I was often the last person in the house home. That sounds like not a lot but things would happen like my parents might order a takeaway, they got what they wanted as did my brother and I had what they had guessed I wanted, and sometimes it was what they thought I wanted, and in the oven to keep warm because I had missed a bus.
The only other option would be child comes with me (40m in car) to high school in town I work in, or another town about 50 mins away in bus as well. This thread is interesting. Some children, like the ones in my village don’t have a choice (unless parents move) and cope perfectly fine.
I think it is different when all children are commuting and when it is a school bus.
Some schools are really strict on punctuality and a child can end up in detention for being 5 mins late, if 40 children are arriving late because a school bus is late the school knows it is not the children's fault and can plan accordingly.