How to have chrome app on my kids iPads?
Two things could interfere with the download.


Parental restrictions would suppress Chrome if your children's iPad doesn't allow that app due to age limits or explicit content filters.
Not using the same AppleID on both devices.


To address the restrictions, go to the settings app and inspect / relax any restrictions to get that one app installed. To address the Apple ID, take both devices and sign out of the App Store from the settings app. Then sign them both in with the same account. At that point, the purchase history for both should be equivalent.