So my friend bought me a set of rims R16 8.5j and 9.5j, rear offset is +32mm. There is a lot of different information about tire size and spacers. What can you recommend?
25mm spacers will be enough? Full stock suspension

 

I'd recommend you sell them to a Corvette owner. Why ruin a 940?

 

Are you asking about the spacers to use or whether a 9 inch rim can even fit in the rears.

The biggest size factory rim is a 7.5x17 ET18 running 225s, so if you are doing a 9 inch, you would be adding 3/4 of an inch to the inside and to the outside. If you look at the wheels you have you (probably a 6x15 ET 25) you can eye ball for available clearance. Note ET's are measured in mm so ET 25 means the rim's center line is 1 inch inboard from the face of the hub.

My guess is 9 inches is really pretty wide and wouldn't fit without some modifications to the fender lip.

My vote would be to pass on this offer as well.