I think you are severely overestimating how many people sleep till 9 or later. There’s no way it’s more than half.

Look at what times are peak traffic or peak public transport. Anyone with kids wakes up early. Most kids do. Anyone who has to be at school by 9 is up earlier.

9am wake ups are for people in their 20s till mid 30s generally. And only if you have a very understanding white collar job. Most blue collar workers and labourers are up much earlier.