The answer to this problem turned out to be that my CRAXDRT.dll file for CR9 was in the Windows System32 folder. Even though the reference in VB 6.0 was pointing to the correct .dll, something about it was wrong.
I fixed the error by copying the .dll into the folder with the rest of the CR9 files, C:\Program Files\Common Files\CrystalDecisions\2.0\bin and redirected the reference here and it solve the error.
So in short, make sure your dll file is in the correct folder with the rest of the dll files.