I update the graphs below at least once a week (on Wednesdays) from time series data on Covid hospitalizations provided by HHS. You can view the graphs by state or by HHS region. Note that pediatric admissions by age group is a fairly new addition to the HHS data file, so it has less historical data than the graphs for all children ages 0-17 combined.
Pediatric Covid Hospitalization Data By State
Pediatric Covid Hospitalization Data by Region

New Admissions for Confirmed Covid by Pediatric Age Group
This data by pediatric age group is a fairly new addition to the HHS data file, so it has less historical data than the graphs for all children ages 0-17 combined.