Unfortunately, Roon does not support seperate libraries.
But there is a solution for your problem.
You should create an extra ‘workfolder’ and add it to Roon in Storage settings* (see remark at the end).
In that folder you move a limited number of your 9000 CDS you want Roon check and ‘clean’ for you, let’s say 300 at a time as an example.
Once you make sure that Roon has added the cleaned albums to your library, you make a new final folder again, where you move the cleaned albums to.
Roon will adjust the file path in its database automatically.
As an example, here you see an album that is in my ModernAIFF folder
I have moved that album to my ClassicAIFF folder (another directory on my harddisk).
Without me doing anything else, Roon has picked up the change in the file path, and corrects the database.
No information is lost.
Regarding adding a folder to the Storage settings in Roon, you have to be carefull not to add it twice:
I have my music split up in 5 different folders, under 1 main folder (with nothing else in that except for an empty ‘Lost and found’ folder, presumably added by Roon or Audiolinux).
In Roon I have setup the main folder with my 5 music folders in it.
If I add an extra music folder inthere e.g. an MP4 folder, it will be picked up by Roon automatically.
If I would add this new folder individually in Roon Starage setup, I would get all infromation in that folder twice in Roon, creating a big mess.
(In fact, I should have added the 5 music folders separately in Roon but it’s OK this way as well).
Hope it is more or less clear, and that it helps