As you may have fiquired out E09 is a heating error code.
For this fault its either the heater itself, wiring to the heater or the control board.
If checking this yourself you need to depending on model pull the dishwasher out and lie it on it back and remove the plastic base cover.
Or if its a solid base panel then you need to remove the right hand side panel and you will see the heater from there.
From there locate the heater and check the wiring blocks on there are tight.
Then you need a multi meter to test the heater and see if faulty.
If the heater and wiring are both fine then you need to remove the main control board from the door panel.
From there open the plastic casing and inspect the board and check for any dry joints or burn marks on the board. If there is then try and resolder it and see if this cures it.
So check the above and see what you find as the E09 code means a fault somewere on the heater circuit of the dishwasher.