As far as I know there is no way to input CD players or other “players” devices into the Nucleus or Roon. Just the files and the streaming services they support.
Look here for a suggestion someone entered for CD playback:
I think if you want to play your SACDs on your Oppo to your audio system you will need to use the Optical or Coax and directly connect it to your receiver or DAC.
Again AFAIK, Oppo didn’t start addressing Roon until two generations after the BDP-93 with the BDP-203 if I remember correctly. I have the BDP-103 and the UDP-203. The UDP-205 has a DAC and is Roon Ready BTW.