If you have links to the peer reviewer studies, I'd like to see them. Not to argue, but actually check
It out myself. I do studies/tests/justifications for my job (not academic) and it's fairly easy to show a causation and correlation. The hard part is the details and assumptions. And as crazy as it sounds I don't mind reading bland studies.
I'd be interested in their methodology, as the conclusions you stated are very specific for something as complicated as all teens and just a 1hr later start.
I used me as an example because my scores got progressively worse later on in the day, and I'd have suffered. I can't be the only teen wired this way, the researchers had to address this and stuff like work/free time/extra curricular activities/how late they stay up/food they eat/home atmosphere, etc. in their setup.