SpaceX, the private company founded by billionaire Elon Musk, has been flying regular missions every six months to allow the rotation of ISS crews.
But the launch of Crew-9 was delayed from mid-August to late September to give NASA experts more time to evaluate the reliability of the Starliner and decide how to proceed.
It was then delayed a few more days by the destructive passage of Hurricane Helene, a powerful storm that roared into the opposite coast of Florida on Thursday.
SpaceX’s Dragon vessel is set to dock with the ISS on Sunday around 2130 GMT.
After a period to allow a handover of duties, the four members of Crew-8 will return to Earth on another SpaceX craft.
In total, Hague and Gorbunov will spend some five months on the ISS; Wilmore and Williams, eight months.
In all, Crew-9 will conduct some 200 scientific experiments.