I'm glad you posted. It is unusual for GH to be 1-2DGH, while you have 8-9DKH in tank and 14DKH in tap (or indeed) change water. The CO2 is reducing the DKH. And DKH is fine as JoeRoun, Klibs and Mattinmd have mentioned.
Mattinmd's comments are well founded. KH is not a part of fish health. It is, in the simplest terms, just for the bicarbonates (in a freshwater tank) that keep PH stable.
In introducing new fish I believe it is important to find out what are the PH levels of the water that they are coming from. PH should be within say .4 to even 1, of their current home and your tank (their new home). If the PH difference is close to 1 or even more, a longer acclimation process will be needed.
I actually believe that GH is more important than PH. GH level is important for best osmotic process's of the individual fish. Angel's can live in 1-15 DGH according to aquadvisor, but if the Angel you buy has been raised in a GH of say 7DGH the acclimation process when the fish is added will be a tough one. Easier to raise the GH to suit the new inhabitant, but also being mindful of the GH needs of your other fish in the tank.
That said, I wouldn't muck around with PH. It can be done, but it takes a lot of effort.
Find out the new inhabitants current water parameters for PH and GH, and post your tanks PH, and I will be able to help more, if indeed help is needed.