You need an output of volts that is more than you need, as in 12 volts to provide 9, then use a voltage regulator to control the output to the end source. Best to add in a battery to be charged and the lights etc., being powered off of the battery with your dynamo or generator charging it. This will provide a more uniform voltage to the end user items.
Voltage regulators from 6 volt motorcycles can be wired in as a regulator. The 12 volt bottle dynamo for bicycles should provide enough power to keep a 6volt batter charged. if the output is equal or less the battery will never get charged, and when the dynamo stops, the lights will fail. This is according to a motorcycle mechanic, I have not tried it, I am still using a 6volt latern battery light.