It's the problem. I often have to guide LLMs 2-4 times to properly write 150-300 LOC changes because I see how the code can be simplified or improved.
There is no way that 9000 lines of code are decent. It's also very hard to review them and find bad spots. Why spent your time in the first place? It probably took one hour for a person to generate it, but it will take ten to review and point out hundreds (probably) problems.
Without AI, no one would submit 9000 lines, because that's tens of hours of work which you usually split into logical parts.
There is no way that 9000 lines of code are decent. It's also very hard to review them and find bad spots. Why spent your time in the first place? It probably took one hour for a person to generate it, but it will take ten to review and point out hundreds (probably) problems.
Without AI, no one would submit 9000 lines, because that's tens of hours of work which you usually split into logical parts.