To clarify, was this an Amazon Kids+ app, or one that was shared/approved to download? If this was an app that you had approved them to download or one that you shared, try removing the content from the Parent Dashboard, so that your child would have to request to download it again:
- Go to the Amazon Parent Dashboard.
- To the right of your child’s name select Settings.
- Select Add content.
- Find the specific app then toggle the switch next to it OFF.
Refresh your child’s profile and see if the app is now gone.