I assume you have installed the Roland UM-ONE Windows 10 driver? If not it is available here:
https://www.roland.com/us/products/um-one/downloads/ What USB port are you plugging the Roland UM-ONE into? It requires 70 milli-amperes from the computer USB port to operate so go into your Windows 10 settings and make sure all your USB ports are set to operate at full power. If you have a laptop, you'll likely need to change your power setting so the USB ports don't automatically remove power to save battery energy. If you have a desktop try connecting to a rear panel USB port that directly connects to the motherboard. Many front panel USB ports are limited.
Make sure you plug the MIDI-IN Roland UM-ONE connector into the rear panel MIDI-OUT of the Yamaha P-80. The MIDI-OUT Roland UM-ONE connector plugs into the rear panel MIDI-IN of the Yamaha P-80.
With the correct Roland driver installed, Music Creator 6 should list the Roland UM-ONE as a MIDI device; does it?
What are your MIDI settings on the Yamaha P-80? Keyswitch F-8 on the Yamaha P-80 leads you into MIDI settings. They are covered starting on page 32 of the owner's manual. Notice there is no OMNI. The keyboard transmits on one of 16 channels. It also receives on one of 16 channels.
Last, what position do you have the 4 position MIDI/PC2/PC1/MAC switch in? It needs to be in the MIDI position otherwise data ismsent to the 9 pin mini-DIN connector you have nothing attached to.