I mean, my post above is pretty much all there is. We basically lived on that schedule until my daughter started online kindergarten. Then we made her roll out of bed at 8:38 to be online by 8:40.
When did the sun set where you lived during that time? I suppose that was a big influence on sleep times?
We live in the Bay Area, so the sun was setting around 8pm since it was spring/summer. Our whole family are night owls, but regular society just isn't designed for that.
Of course now that they have regular school they have a regular bedtime that still gets them 9+ hours sleep (actually closer to 10 hours), but they are still groggy and slow in the morning because it is not when their body wants to be awake.