Hello lindsaybethleeder,
Thanks for using the Apple Support Communities. We understand that you're looking to unpair your AirPods from your child's iPad. Looking over article, Switch AirPods between iPhone and other devices, it does appear that since both devices are signed into your Apple ID this would be expected behavior and removing the AirPods from the iPad would also remove them from all devices on your iCloud account.
However, you can adjust the settings on the iPad so that your AirPods do not automatically connect to that device anymore. To do this go to Settings > Bluetooth on the iPad with your AirPods in your ears. Tap the info button next to your AirPods in the list of devices, and then tap Connect to This iPad > When Last Connected to This iPad. Your AirPods should not automatically switch to the iPad devices audio unless the iPad is the last device it's connected to.
Another option would be to disable Bluetooth on the iPad. To do that, go to Settings > Bluetooth and place the slider in the OFF position. If you need to keep Bluetooth enabled on the iPad, another option would be to create a child account and set up Family Sharing. You can read more about this here: Family Sharing and Apple ID for your child.
Hope this information helps!
Best wishes.