Why can't they progress in motion, on a repetitive pathway across the planet?
As they progress into wheel building, they would naturally be able to cover much more ground than the rotation demands, and thus stay on sites for increasing durations; say ~1-2 weeks, and appoint a priest-like caste to keep them on schedule.
As their numbers increase, they would expand in a line-like formation, with specialization developing based on your placement in the hemispherical society.
- The front-line leaders would be a militaristic-style class of the strongest warriors, clear brush and obstacles in the path, neutralize threats, prep the 9 year old edifices or what remains of them, upgrading as technologies developed in the middle segment reached the front lines, setting animal traps.
- Those behind them would be a construction-like caste, doing larger rebuilding like tasks, making the structures usable again, upgrading them with new technology, more preparation for the societal bulk
- Those in the middle would be the largest bulk, and include the elderly, young, infirm, academics, the wealthiest and industrial base, building products and items with the prepped foundations ready for them by the two groups ahead of them and innovating new technologies to help the entire tribe
- Those trailing the middle would lay the dead to rest, close up shops and start the storage process for anything destined to remain for the 9 year cycle
- Those at the very end would be just missing the nighttime, performing scavenging like tasks and dying frequently if they made mistakes, and could be similar to an untouchable-like caste. There could be some additional tasks available to the rear, such as planting night-growing species to harvest in the next migration, or releasing night-breeding animals to make a robust population of huntable meat (or frozen, preserved dead meat) for the leaders at the next arrival.
As societies develop, better forges and tools are left scattered across the planet, as well as deepening mines with each migration, thus moving from hunter/gatherer to wood based tools, to stone, and then metals.
Some tribes may take differing paths across the planet's surface; perhaps joining in some places where their cultures and diplomacy aligns, and avoiding or desecrating each other's sites where cultures differ or diplomacy breaks down.
While there is certainly a penalty in development time for this migration relative to sedentary/agricultural societies, some benefits include constant necessity for innovation, very quick disposal of irrelevancies to survival like art and burials and the inability to wage war in the traditional sense, with large lapses in communication between the front, middle, and rear of the 'tribe'/'nation'.
I would presume they would eventually lay iron tracks since there is a singular, well traversed route that would allow for train-like constructs to ride on, though perhaps built from wood and foot/pedal powered at first, which would then allow for a planetary rail network, with then bicycles and cars coming along and allowing mobility between tribes/linear nations.
Once railways and interconnects are built, it would be conceivable to have powered travel to the emerging dawn, and full 9 year habitation, with a travel cycle every 9 years, which is longer than many humans stay in one place on Earth.