This brace needs 1913/picatinny interface and PAK-9 pistol does not have 1913/picatinny interface. You will need to purchase this adaptor ( https://stormwerkz.com/stock-adapters/ak-pistol-adapter-type-2/ ) and install it on PAK-9. I hope this helps!

Hi Oswald and welcome. Yes, you will need the Picatinny Rail Adapter : https://stormwerkz.com/stock-adapters/ak-pistol-adapter-type-2/ ----------------- The end result will look and function as this : youtube.com/watch?v=r7vSEm1J2y4

Hi Oswald, it will fit with this adapter >>> https://stormwerkz.com/stock-adapters/ak-pistol-adapter-type-2/
Be advised, adding this stock to your pistol will turn it into a SBR and require a $200 tax stamp and registration with the ATF BEFORE you are even in possession of the stock.
You can, however, add a pistol brace with no ramifications >>> sb-tactical.com/product/fs1913/
Stay safe & have a great day!