I'm not sure it's even possible. Our h.s. team skates six days a week and add to that the ranting belittling meetings, the 'film sessions' and pasta parties and fund raising events...I now see why so few of them want to play hockey after high school!
If you make varsity you will have no time to play club. If you are on a JV team as a u14 or u16 you need to play club(if you make it) because jv hockey is terrible. Like the previous guy said , you have to still make HS your priority and do not advertise it , most jv coaches don't care, some do but better to keep your mouth shut
Maybe at a low level high school JV team you could pull it off with just a couple skates a week and a 20 game season...but in that case why play low level JV? For a real varsity high school team it would be very difficult and you would be looking at a combined 50-70 game season if not more.