I am using the CF850CX primary for moving snow. The machine is perfect for the task, but there is only one thing i really dont like about it, and thats that instant kick when the clutch engages. Now it kind of "kicks" forward or backward. Is there any way to make the variator engage softer?

[2015 Z Force 800 53/Trail EPS]

Yes. Change the spring to one with a lower RPM engagement or go with slightly heavier flyweights.

Exact same thing for me. I joined the forum looking for this exact information.
I don't know anything ATVs....

What modifications should I do to the CVT to make it as spongy as possible at the start?

MSC and RNG plus others sell Primary Clutch kits to fix this type of issue, I know RNG targets a fix to this issue with his kits.
The kit typically incldues a replacement spring and weights.

I'll let you search up RNG and MSC if you don't then who they are, rather than have the links removed from this post.

As I am relatively new to this forum, are we not allowed to post links?

[2015 Z Force 800 53/Trail EPS]

As I am relatively new to this forum, are we not allowed to post links?

Links are fine. I allow most everything unless it relates to spam or advertising or promoting a business interest from a non-supporting vender or party. Go for it. Help is always welcomed here.
 

I just got better with the throttle on mine.
I did however, take a little bit of slack out of it too so I could feel it pulling up better.