Hi,
It is possible to use the DAC in a CD player for other sources provided the device has digital inputs. I found the manual for the AR CE8 online and it does not mention a digital input. In my experience, digital inputs on CD players are relatively recent additions.
You can connect several sources to a DAC such as computers, streamers, CD transports and what have you, but you are limited by the various inputs the DAC has. There will be an input selector knob or switch.
ghdprentice is absolutely right in suggesting getting a dedicated streamer for best results,and using Qobuz.