Have installed app on childs ipad entered activation code but the device doesnt show up on family portal
When you installed the App, did you choose to 'trust this application' and allow permissions? When you open the App now, do you see 4 circles (that include areas such as access period and device owner)?
If you don't, it may have not completed activation. I'd recommend generating a new key and ensuring that all things are approved during the enrollment process/