09 buzzing drivers side

Everybody on the internet seems to have some idea what "normal inverter noise" is, which is often something else entirely. The inverter is darned near silent when it isn't handling significant power accelerating or regen braking. One of people's favorite candidates for "normal inverter noise" is a whine you can hear pretty well with the hood up that is in fact made by the throttle body motor.

But when you describe any sound that lasts around 2 seconds at a time and repeats at times, my first, second, and third guesses will all be the brake pressure pump. It doesn't have to sound clacky and loud. I sometimes describe it as a distant rattlesnake, or joy buzzer. There's a range of variation in the sound; some are pretty quiet.

It's a pump that runs whenever needed to shove more brake fluid into the pressure accumulator so there's enough pressure there to work the brakes. Takes around 2 seconds to do that. Pretty certain to be what you are hearing.

 

The sound when you turn off the car is most likely associated with the pumping of heated coolant into the thermos.

Periodic creaking sounds can come from ABS pumps, inverter pumps, heater pumps.

 

The car will use a pump to store hot coolant in the thermos at shutdown; this can become a familiar, recognizable sound also. It runs for rather more than just 2 seconds to do this, and does not repeat.

You may, when making the car READY a following morning, notice the same pumping sound for the same matter of seconds just before the engine starts, as the saved hot coolant is pumped back to the engine to pre-warm it.

Once familiar with both sounds (this coolant pump, and the occasional 1 or 2 second rattlesnaky buzzes from the brake pump, neither sounds very much like the other.

 

I agree that the sounds are different.
In absolute silence, from the moment of switching on until the moment of starting the engine, there are sources of sounds - the thermos system, the inverter pump, the ABS brake system.
If the climate control is on, then the sound of the air flaps is also possible. But it is unlikely to be repeated periodically.
Pumping pressure into the brake system when it is worn out is the most likely event.

 

You can easily check the brake fluid level by opening the hood of the engine compartment.

You can also check the level in the tanks for other process fluids.

 

The noise you hear is your brake actuator. It's a very common problem on the Gen 2. I've had that cycling going on with my current car for over a year. It's normally due to an internal leak causing accumulator pressure to drift down and then the pump runs for a couple seconds to re-pressurize it. Eventually, (it may take months or years) the actuator/accumulator/pump assembly will not be able to keep up and the car will throw a code. I've replaced a few, but on my current car, I'm just going to see how long it can go as it is

Toyota 44500-47141 Actuator Assembly, Brake .... if you need specific terminology.

 

That noise is most likely the transfer pump moving hot coolant from the engine to the storage tank.
The inverter cooling water pump runs when the car is ignition-on, or READY. Car off=inverter cooling water pump off.

 

It is enough to remove the relay from the socket to stop the voltage supply to the system.
This is usually done when eliminating leaks in the brake system or replacing parts.