A/D input channels have very high input-resistance, so they will not load down your ckt. However, you can blow
the Arduino by putting > 5V on an A/D channel [or any other pin]. To help preserve the Arduino for your initial
case, move the 2K R to between the pot wiper and the A/D input. Then you'll still get the full range.
HOWEVER, if you apply 9V instead of 5V to the pot, then you run the risk of blowing the A/D again. The usual
means of applying > 5V is to use a voltage divider, but they only work correctly if the total resistance is much,much
greater than the source resistance, eg, 10K for the pot, so you're in trouble here.
If you're forced to use 9V on the pot, and 10K for the pot value, then you should use an opAmp follower ckt
between the pot and the voltage divider.