I dunno, I expect they just managed to avoid a lot of the glaring technical issues and played on a PS4 Pro. I can't see how any site would give it any higher than a 7 with how many bugs, glitches and performance issues it has.
I've had fun with the game, but the game really isn't that great from a technical level. It runs really poorly on my regular PS4. Side quest random generation is borderline broken with it constantly generating the same target location. The way the game generates units is completely flawed and puts them in places they can't move (see the wolves in Jim's video, but I also experienced it when the game spawned some troops off the side of the map underwater). The game has bad pop in, both textures and models. The voices glitch in and out randomly.
Fortunately, technical issues in theory can be patched, so I really hope they pick up the pieces.
This is fair enough. One would have to be either very cynical or very blind in order to not criticize the technical issues and admit the impact they can have on performance, even if they don't get in the way of the experience all the time. That's an objective problem with DW9 and, based on this alone, I wouldn't exactly give the game a high score either. I am also hoping that a couple of patches will help reduce the many glitches.
What's much more subjective is whether the game is "fun" or not. If you go by Jim himself, he didn't feel a single ounce of enjoyment, but that's clearly not the case for everyone. We can debate the various buggy aspects of the open world design, acknowledging it is mostly an empty world out there, and yet disagree about whether or not there are any positives to it.
There's also room to discuss the AI behavior, which seems to only be strictly passive on the pre-release review copies and even then when played at normal difficulty or lower. If I had to play the game under those conditions, I'd surely be bored to death, but I was lucky enough to see more videos and notice that the difficulty settings do make a difference here.