Can sweat&moist cause redness between big toes of a 9M baby? He swims every week. Also uses shoes a lot. Have you seen this on babies? Is it common?

It happens. Generally a kid that age should avoid shoes. Many trap moisture and can lead to the equivalent of a diaper rash, especially between the toes.Rubbery soled socks are the only things I put on kids feet at that age.Any shoes you buy for show, should breathe well while on the feet. Patent leather or plastic are the worst offenders.