By "hurt" it I assume you mean cause premature wear and that we are discussing a new or like new pistol in perfect working order?
Yes, by all means shooting above pressure +P or +P+ ammo in your firearm will accelerate the wear on your firearm.
Now that said, the K9 is a very strong firearm made from high grade steel.
The difference in wear in an alloy frame is often 30% reduced service life if the user was firing +P or +P+ ammo for the entire life of the pistol.
The original Kahr numbers provided when the pistol was first produced placed a service life of between 25,000 to 30,000 rounds with 9mm NATO spec ammo.
Will you be shooting 7-8,000 rounds or more of +P+ ammo?
If the answer is no, then by all means use the +P+ ammo as much or as little as you would like. Your pistol will not "detonate" and you will have a round that performs as well or better than most of the .40S&W loads out there with less recoil and one round of increased capacity.