On the Siemens dryer, F09 indicates a fault in the heating circuit.
Unplug the appliance.
You'll need Torx driver or bits for the screws.
Take the bulged cover on the rear off.
Look for the thermostat with a small button on it. (Depending on the model you have)
Press the button firmly to reset the thermostat.
Refit the cover.
Clean out the filter and condenser.
Clean out the condenser chamber.
Try the machine again.
If all is well, it will be working again.
If still no heat, you'll need to test the heater using a multimeter to see if it's open circuit.
Check it out, see what you find and get back to me if you need more help.
But i know you said you wanted to try and fix yourself but not sure if you know but all Siemens appliances come with a 2 year warrenty. So as you only got it in 2015 then it will still be under warrenty so you could give Siemens a ring and they will fix it free of charge for you. But if you want to do youself then try the above and see what you find and let me know.