@Valentin_Sh 

here is the screenoshot

and i went through all 19 pages -- no such device with MAC 

@Valentin_Sh 

Are the devices you are seeing all apart of the same subnet? (ex. 192.168.0.x)

What is the IP of the router, and its subnet?

Looks like you have different subnets going on rather than just having one.

Hello @Tony 

Yes, all devices in te same single subnet with 255.255.0.0 mask.

Router internal IP is 192.168.0.1

I have assigned static IP to the device by MAC 

@Valentin_Sh 

Undo any static addressing be it on the device (iPad) or on the router so the iPad grabs an IP via DHCP, does it then show up on the list when doing parental control?

Didn't appear in the list. I tried with wired client -- assigned the IP by MAC and Device still visible in the device list for parental control selection.

IPad still not visible. With and Without binding

@Valentin_Sh 

I know with the latest iOS there is a feature where it can randomize the MAC address as a security feature. Has that been disabled?

Here is an article on how to disable that: 

https://support.apple.com/en-us/HT211227

Once that is done, remove any reservations or static assigning anywhere, verify the DHCP client assigned the iPad and IP, then look for it on the parental controls. If that checks out then assign the IP to the MAC in the router.