You should be able to use any one of those digital outputs into a DAC and then connect it to your SA-9100. You can get an inexpensive DAC, like the Audioquest Dragonfly, Parasound Z-DAC or Shiit MODI-2 to get you started. Just put it in-line between your digital source and the SA-9100 and you should be good to go.
I'm not up to date regarding DACs that use HDMI. However, I have used optical, coax and USB with no issues using DACs that support those connections.
For $100 new, or even less used, you could try one of the DACs I listed above. Will get you started in the right direction. Removing the HT receiver from the mix will be a good first step toward sound quality and simplification of the overall system and operation.
I'm not up to date regarding DACs that use HDMI. However, I have used optical, coax and USB with no issues using DACs that support those connections.
For $100 new, or even less used, you could try one of the DACs I listed above. Will get you started in the right direction. Removing the HT receiver from the mix will be a good first step toward sound quality and simplification of the overall system and operation.