No, Liverpool were playing his style right away. They just weren't as effective, and thus didn't have the results (in terms of goals scored or conceding goals). He was never pragmatic from week 1 or week 8.
The difference is that, Ten Hag started off similarly, but the players were so awful in their mentality (nervous to start, no fight after conceding, and no effort) that he probably became a little more pragmatic in his instructions. It's quite clear to see that the way we were playing in preseason is different from now. And I'm not talking about how good we are in executing his instructions. It's clear that the instructions are not the same as in preseason. The easiest way to tell is how we press. We are not nearly putting in the same amount of effort as before (nor are we as coordinated), and that has benefitted us somewhat in that we're a bit more compact and do not leave as much space for the opposition to exploit.
But again, I completely understand why we're like this. I think Ten Hag wants the players to regain their confidence. It could also be because he doesn't trust key players to execute his usual instructions (De Gea for instance).