What is the reasoning for that?
IMHO I don't agree. By the time kids enter high school, they need to start preparing for the real world. The majority of people work day jobs, of which the majority are 8-5. Moving school to 9 or 10 am only makes them have to stay at school longer (5 or 5:30) etc.; then they still have homework when they get home. If both parents are working, this will make it harder on the parents to get dinner done, and homework not to mention any after school activites the kid might be involved in. All parties involved will be staying up later, just making it harder on everyone to get up again in the morning. The kid might not have to be at school until 9 or 10, but the parents still have to be at work at 8 or so, meaning they are still doing the same job on less sleep. Teenagers tend to want to stay up late anyway, letting them off the hook of being responsible by getting up early for school only encourages them to stay up later. It's a vicious cycle and the parents will suffer.
Kids need to learn that the world does not conform to their whims and desires. Unfortunately, that's not what the lesson will be here.
Again, JMHO.