When I was younger I always bought larger shoes because my foot was growing quite a bit every 6 months. If your shoes are larger and you’re waiting to grow into them, then double up on socks. Don’t let your foot slip around and potentially cause blisters. Still, it’s probably best to just buy shoes that fit your foot. If I had to do it again I wouldn’t have bought bigger shoes.
John Wooden, the famous UCLA basketball coach, used to sit his players down on day one of practice and teach them the importance of not getting blisters. He even said the secret to his success and 10 national championships was the way his players wore their socks. His tip for not getting blisters, no wrinkles. Put your sock up tight, feel your heel, sides of your feet, and ankle. Make sure there are no wrinkles! Wrinkles cause friction and friction causes blisters!