If you receive prompt medical attention, it's likely that you would survive a single gunshot wound to the kidney, although it's still a pretty serious injury.
A ballistic injury to almost much any part of the body has the potential to be fatal, depending on factors such as blood loss and the damage the bullet does internally while travelling through you.
The "safest" part of your body to be shot in would be the hands or feet.
Would I survive a gunshot wound to the kidney?
To understand the damage a bullet can do, you have to take into account things like velocity and gravitational trajectory.
When a high-speed bullet travels through a body, it pushes aside or crushes everything in its path. Not only that, but the energy of the bullet travels in shockwaves through the body, pushing soft-tissue and organs like a mini-explosion inside you.
The bullet may also fragment into smaller pieces causing greater internal damage,
This is what causes the majority of damage.
So if you were shot in the kidney,factors like what kind of weapon and bullet were used, and how far away the shooter was, will impact greatly on your survival rate.
The kidney and abdomen is relatively soft, so there'd be nothing to absorb the shockwaves of the bullet. Instead, you'd expect the bullet to do substantial damage to the surrounding tissue and organs.
Here's an interesting video about wound ballistics that may help you visualize the concept better:
I'd also recommend reading the US National Library of Medicine's documentation of renal GSW's.