What a waste of money. Anything larger than LM-5 is a waste.
China should instead focus on cost reductions and rocket reuse.
You can do on-orbit assembly of whatever you need to make a Moon or Mars mission.
Those ultra-expensive Saturn V like launchers are pointless.
The Soviets made Energia and it was relegated to the trash heap of history.
At best they continued the RD-171 rocket engine design. The rest was pure waste.
Of the Saturn V rocket only the RL-10 engine was retained into use.
Elon Musk and Jeff Bezos' massive rockets (TSTO Starship, New Armstrong) are pointless also.
Even if they are reusable no one needs that kind of payload capability. Or will for the next decades.
Just look at Korolev and Chelomei's late designs for a manned Mars mission.
They didn't use chemical propulsion for manned Mars missions. They used nuclear or solar-electric propulsion.
This means the required payload mass is way lower than with chemical rockets.
I sympathize with the desire to cut costs and standardize on a more affordable rocket.
However, I think that if a country has grand ambitions like China, a heavy-lift rocket makes sense.
Energia didn't 'fail.' It was a great booster. However, it came at the wrong time [dissollution of the Soviet Union]. The new Russian Federation could not afford the payloads that would fly on Energia.
If the Soviet Union had continued, there were all sorts of payloads for Energia. Giant panels to bring artificial light to Northern towns, disposal of dangerous waste, and more importantly, the key infrastructure of a lunar base and things like Mars sample-return.
I remember reading all about Energia on the Astronautix website. The author lamented Energia's cancellation, pointing out that the USSR could have used it to leapfrog U.S. achievements, including the creation of a manned lunar facility.
If you are building a lunar base, for instance, you can simply land larger objects on the surface with a heavier rocket. In base and station construction, it's helpful for the engineers to launch everything at once. Skylab was one-launch. How many launches was ISS? So much time and space wasted just having the modules small, and each with mandatory docking components.
Imagine the kind of station China could launch with LM9. Full-sized comprehensive modules, fully-tested on the ground, and placed into orbit. They could have greater capabilities than the current station under construction.
Creating stations and missions by docking components in orbit using a medium rocket is great, especially if you need to get something done in the near-future using existing launch infrastructure. But if you have time and money, you can have a more robust capability and more ambitious objects. Docking is something of a pain, and introduces uncertainty as compared to a large monolithic payload.
Giant boosters are not incompatible with reusability. They were looking at flyback boosters for Energia even way back then, another thing the Soviets could have leapfrogged the U.S. on had they continued. LM9 can upgrade later with reusable components, just as Energia was planned to.
I agree that, in the context of the space race of USSR vs USA in the 1960s, it would have made more sense for the Soviets to forget about giant boosters, and focus on getting payloads to the moon via docking. The heavy booster would only have succeeded had Korolev lived, or if the design bureaus weren't competing over resources. Getting some kind of EOR Soyuz to and from the moon would have succeeded more readily than fiddling with a heavy lift rocket.
But that is not the present context. China set out both the time and the money to develop a HLV that can support serious ambitions starting in the 2030s. In that context, LM9 arguably makes sense. Yes, markets for the booster rocket are everything.
If a booster rocket is to be confined to the needs of the existing launch economy, then LM9 doesn't make sense. If we assume that China has goals for space exploration outstripping that of other countries, and can fund this program, then LM9 helps relieve the burden faced by a robust exploration program. It's all about the customer or client in launch services, and China is a customer that could potentially need a large rocket.