I have a Bosch Aquastar 6.0L
I also get an error 9 code after the wash in finished and the water is cold and residue is left on the plates.
I can also confirm my googling provided answers that this is a heating circuit issue as well. As far as I can find it can refer to control board failure, the "heat pump", the heating element or a thermostat.
We believe ours failed before 2 years but we only reported it some months after the 2 year period and Bosch therefore refused to do anything about it.