Yes. It is generally safe for kids to use the word OC. In that viewpoint, OC refers to “original character”, which concept is common in storytelling communities of fans and drawing. Some OC stuff can mature-related, other settings in a manner of peaceful. It is actually good for parents to watch out for which OC is being shared. Always check if your child is using the platform for what they are age-appropriate. Parents should teach their kids What does oc mean, because it help children to use word in right context.