I know in mass if your a good player with decent size it is better to play on a d1 hs as a freshman vs staying back, to be on a future prep team along with FS bantams. If your really good prep teams will reach out sophomore/Jr year if you want to go that rout.
In CT there are two ways to go. Find a half season team if your player wants to play high school as a freshman or commit to the team even though you might end up leaving and paying for the whole season. From a CIAC standpoint, your player can tryout for high school and have a double roster overlap for a couple weeks while the HS team is forming.
How big is the HS roster? Does the coach encourage freshman to stay on their bantam teams? How many players make the varsity group as freshman?
Yes every year is different, per Catholics d1 it may be hard. in strong town HS it depends on what they need, how good, size, competition at position. Some years easier, some not. My son will be a freshman next year but is a U15 (late birth month). So we will play half season U16 and see if he makes the HS team, not many options for full season U15/U16