Ok, then here is my proposal: Run the motor on unregulated 12V directly from a 12V SLA. At 1A, to a first approximation, a 10Ahr (Amp-hour) battery will run the motor ~10hrs, less if you steal some power for servos and LEDs. Use a linear regulator, like a LM7806 or an LM317 with appropriate resistors to reduce the 12V to 6V. The servos likely draw a low enough current that using a switcher is not worth the effort. Look up the forward voltage of the LEDs, and add enough of them in series to add up to ~9V. Calculate a resistor that will drop 12V to 9V (3V drop) at the current you are going to be operating the LEDs at. Do the test in the running car to see what the charge rate will be.