Lower CR = lower N/A efficiency, so yes, it will spool a little bit worse. Nevertheless, I don't think 0.5CR should make a difference of 500rpm. I suppose that there's something different affecting your spooling time.

CR does not affect spool in any noticeable way.

There's something else completely screwed, the bigger intercooler is not going to give you 500rpm spool difference.

Most likely causes:
1) Boost leaks, probably not pressure tested.
2) Incorrectly set turbo actuator
3) Damaged turbo
4) Wrong cam timing

Either way, CR makes no difference on this.

Think of compression ratio as a brick wall. If you are not running special fuel, and just stick a big turbo on, there will come a moment where you can not run any more boost without melting the engine, because the timing efficiency will be so low and the EGT so high.
It's not a "more power, different off-boost response" kind of thing. It's more a "if you want to pass this amount of HP/TQ on pump fuel, your CR is going to have to be this or lower".

Yes, if you are already maxing your turbo on the higher CR and EGT is not getting too high, then dropping the CR will do very little in power terms.
But running a GTX3071 you're gonna need 2.3+ bar boost on the engine, and anything over 1.5 will give you problems on 9.5 CR and normal pump fuel from an EGT standpoint.
So you will be stuck making max 350-400hp on the turbo (with all the associated turbo lag), when you could be making 500 with the correct setup.

Another thing with a GTX3071 is you need to upgrade the valvetrain, because 7200 rpm will not be enough to do a 1->2 and 2->3 shift properly, and anything higher has a risk of floating valves on the 1.8T.
At a bare minimum you need solid exhaust valves and uprated springs to rev to 8000 rpm or so.

As for the performance - if you did a blind test on correctly tuned CR8.0 and CR9.5 1.8T on pump fuel even on the stock turbo you wouldn't notice anything, apart from the marginally higher fuel consumption on the CR8.0 car. And the CR8.0 would still make a little more power when both are tuned to the maximum.
The only reason the CR is pushed up so high on these cars is for fuel efficiency.
Unless you are planning to run the car primarily on ethanol or VP MS109, you absolutely need to significantly drop the static compression ratio if you want to make any power.

I personally think OP has not done his homework. For the type of mods he wants to do, a GTX2860 would be a much better turbo.
With the GTX3071 the car won't make any more power, and will have a ton of turbolag.

So i get main answer - this is not CR problem.
IC bigger about 50percent and pipes lenght about 20 perc in slow-spool car. Intake checked with pressure (all intake system new, also ckeched after welding). DV doesnt leak(tested and tried to replace it). Turbo actuators set identical in both cars. Cam timing good(i have had set timing in 1,8/1,8t engines many times - always double check before adding valve cover). New chain, new OEM VVT. That part about  damaged turbo sounds bad, because there is almost nothing left to check

There is absolutely nothing wrong with that approach, imo.