Your going to enjoy the Sony x800 on your W9 because the x800 gives you some added control over the video image. When your watching standard DVD's and you hit the options button you have a choice called "Video Options" in here you have 5 choices. Auto (default) Theater Dark, Bright Room, and Custom 1 & 2.
Bright Room - works the same as setting the back light to full
Theater Dark - drops the brightness and contrast so the image is not so intense when viewing in a blacked out room.
Custom - Allows control over the contrast, brightness, color, and 3 other options that I haven't messed with yet.
The custom is cool, because you can create a greater depth to the video image, kind of like a false HDR look. Example, I loaded up Peter Jackson's King Kong (DVD) and from the "Video Settings" Custom-1, I set the contrast to 1 (default is 0) and the brightness to -1, color left at 0, and it creates better separation between the dark and bright without crushing or clipping creating that extra depth. (The upscale to 1080p was very close to Blu-ray quality).
On custom-2, I set the brightness to -2 and the contrast to 1, but I think for DVD material this might be crushing blacks a little, but on "Hacksaw Ridge" Blu-ray i thought the image looked great with greater detail in the darker areas. For the Mastered in 4K disk like Spiderman 2 and UHD 4k John Wick I set custom-2 to -1 brightness, 2 contrast for a HDR look.
I think the Sony x800 equals the OPPO 203, and Panny UP900 as for 4K player quality, and better image quality than the Samsung K8500. Only issue I have with the x800 is the inability to produce and send BT2020 to the TV when converting HDR to SDR. Something the Panny can do with the HDfury linker.
From what I read in other forums the guys over at HDfury haven't received the x800 yet to work on a solution to get BT2020 out of the Sony. So we'll have to wait and see if that's possible. If so then the Sony x800 leaps ahead of the panny.