This message means that the app's developers have marked it as "incompatible" with your kid's device.
Instructions
Sometimes, you can fix this issue by updating the software on your kid's phone or tablet.
On your kid's phone or tablet, open the ⚙ Settings app.
Tap on Software Update.
(If you cannot find it, tap the 🔎 magnifying glass to search for it.)Check for updates and install them if needed.
Head back to the
Play Store and search for the app again.
If it still says "This app won't work for your device," then that means your child's current phone or tablet won't work with that app.