There is only way Cepheid variable stars can be brought into HSC Physics assessment, which is indirectly through Module 8 - Origins of the Elements - Dot point 2 - "Investigate the evidence that led to the discovery of the expansion of the Universe by Hubble". This dot point sits uncomfortably with the main theme of this unit, which is nucleosynthesis. It probably won't be examined, but in theory it could be.
To examine this dot point would most likely require an extended response question of about 5 to 6 marks, something along the lines of, "Describe the evidence used by Edwin Hubble to justify his explanation of the recession velocities of galaxies." Hubble's discovery relied upon a distance scale that was calibrated out to 6 million light years. He used a "stepping-stone" approach. For the first 1 million light years, he used Cepheid variable stars to calibrate his distance scale.