can "File system check exit code is 8" be repaired? I have a startup disk from my old computer with error File system check exit code is 8.

can this be repaired?  I would like to use it to migrate files and settings to my new computer, it is an SSD if that makes any dif.  I do have the filed from this disk backed up but not the system settings needed for migration assistant to move tho new mac.
Generally speaking it depends on what you mean by repaired.

That error indicates that the filesystem on that disk is damaged. The good news is that if you reformat it the disk will still be usable. That is also bad news, as you may have noted.

You can try running disk utility on that drive a few times (3 - 4) and see if is repairable. Depending on the filesystem in use on the drive you may be able to use something like DiskWarrior to fix the disk. But beware that DiskWarrior and pretty much all disk repair utilities can't repair APFS volumes (yet).

If that is the case you can try a data recovery utility or sending the drive off to be recovered for you, which can be expensive.