Servo motor with 9V battery
A 9v "transistor" battery is unsuited to powering servos - at best it might work very briefly.

Use 4 alkaline (or depending on the servo ratings, perhaps 5 rechargeable) AA or AAA cells to power the servo.

Either power your Arduino from something else, or get a 3.3V version that you can operate from a low dropout regulator on the 4 or 5 cell pack.

A 7805 has a high dropout voltage and is out of place in a battery powered system.