Are the Samsung SWA-9000S or Samsung SWA-8500S compatible with the soundbar?
And what is the exact difference between
Samsung HW-Q70T and the Samsung HW-Q70R?
Yes, both compatible, with the SWA-8500S being the recommended model.
The HW-Q70T is the newer soundbar of the two, whereby the subwoofer has been shrunk, but the "acoustic beam" (=> sound placement in the room) has been improved.