Well, not without doing a complete factory reset and wiping the device.
The Google Play Store version of curbi can be bypassed if your child knows their way around the Security settings on Android.
If you have a problem with this, there are a few things you can do.
You can install the curbi kids app direct from curbi.com here. This version cannot be bypassed or uninstalled.
Android 7 and 8
On Android 7 and 8, the only way to remove curbi is to get to the Settings app. Since you can block any app using curbi, just go to the Apps listing on your curbi Parent account and block the Settings app. This will prevent your child from opening Settings at all.
Removing curbi from an Android device requires your curbi username and password.
You can also temporarily override curbi's rules on a device by entering your PIN.