Rule #1 a 9V battery is not a power supply. Rule #2 9V battery does not run motors. You might get it to work sometimes maybe but you will be using a lot of batteries. Typical drain for a 9V battery is about 15 - 20 mA. It has about 550 mA Hours capacity. This is for a 9v alkaline battery. FYI the Arduino Uno consumes around 45 mA way more then the battery rating, this does not count your sensors and motor(s).