cab request

I wanted to have a common team timings so that some do not have to wait for others if they have dependency.
One of the senior folk who has been around for all his time here was coming by 12 and leaving late and sometimes by cab because the last bus left at 9. He would do so by sending a mail demonstrating that he has left late in the day.
I confronted him and asked his reasons and he started helath etc., I tried to explain that I was trying to bring in a culture wherein people work in day and help each other in common hours of work.
He said no one has questioned his cab request in the past. There are things that one learn beyond 9 for the benefits of the team. In his last project people left by cab almost on daily basis because they were doing another project in day and theirs in the night. The other team members were not available at 8:30 PM.
The other team members said he was not available at 10 AM.