The 9000 uses two motors. 1 is for driving the timing/meter mechanism. The other is for driving the upper and lower pistons. These communicate through a simple set of micro switches.
In the home position, the timer motor does not turn, it should turn on when you turn the knob. The timer motor has a view window where you can see the motor turning. You will see that a microswitch gets activated when you urn the knob one click, this is what connects power to the motor, the motor then continues until the cam rotates 360 degrees over the next couple hours and the micro switch returns to home. This valve is an engineering work of art. You will need to spend some time to understand how it works. This should give you a good start.
Now... how old is the valve? It may be time to update the valve. The 9000 has mostly been replaced by the 9100SXT. The 9000 valve body is brass and has some known longevity issues. The body can become damaged in the lower center section under some water conditions. The newer electronic control adds some nice bells and whistles. but... the old mechanical design is still highly reliable and long lasting. Post some pictures of your system so we can see exactly what you have.