I know everybody's family is different. I tend to be a pain in the butt if you ask my kids but they text me at various times during the day. Especially after school if they are going to be late or have an activity...etc.
I'm curious about her afternoon schedule. Not that it has anything to do with her going missing because she went missing during the morning but I'm curious about what Sierra's day was like typically. Did she ride the bus home and got home at a certain time everyday? Was she involved in any after school activities that might make her come home later? How did she get home on those days? Etc.
I see your point though. But again, everyone is different.
Where I lived and when I grew up (mid 90s for teen years) there were quite a few kids who were unsupervised/ untracked until dinner time since both parents worked until 6 or 7. Kids hung out with friends and got a ride with them or did sports or went home right away. Those parents pretty much left the teens to themselves for the afternoon.
Her normal routine would be helpful, I agree.