My car is only 4 seats
Yesterday I had DD1, our foster child, DD2 and a friend here so more people than seats in the car.
I had to take DD2 plus friend to a birthday party in town, so left DD1 here on her own (about 20 minutes)
She's sensible, has a mobile phone, plenty of neighbours around. She walks to school on her own and goes out with her mates anyway
DH was a bit shitty about it