My car has been sounding different and running hard

The transmission has been jerky, and weird electrical issues have been occurring.

First, the noise sounds like it is coming from a belt on the left side above the alternator, but I cant tell. Also, when I am near between 1200 and 1500 RPM, I get a whining noise. I have also have been seeing an increase of about 500 RPM across the board (eg. At 40mph on a flat road I typically see 2k RPM but now see 2.5k). When my car shifts, it jerks and it is pretty noticeable (its automatic). As for the electrical issues, I have been seeing the light that illuminates my temperature control flicker off and on for about 5 mins maybe 1-3 times per hour or so. While testing my battery, I saw that it pulled to about 9V when starting, but leveling off at 14V when running and 12.8V when the car is off.

Today, I drove about a mile to walk a friend's dog while they are away on my way to work. Their driveway is steep so I applied e-brake before turning off the car. Upon turning my key in the ignition, I got no response, not even a light came on, nor did the engine crank. After 3 attempts, I released the e-brake on a hunch and when turning the key, it started fine. My radio and clock were reset though. I had no further issue with it today. At work, I cleaned the battery terminals, I don't know if it helped or not, but oh well. I realize this is long and I appreciate any feedback.

Thanks.

My car has been sounding different and running hard, the transmission has been jerky, and weird electrical issues have been occurring.