Bitoque,
It sounds like you have loaded the whole AC 9 library twice.
or you have the un-extracted form of the library
called "ArchiCAD Library 9.pla" and the extracted form of the library
called "ArchiCAD Library 9.lib" both loaded.
Perhaps because they are in the same folder, which
they should not be.
Check and see if, inside the folder
called "ArchiCAD Library 9", there is a folder called "ArchiCAD Library 9.lib"
if it is, then drag it out and put it at the
same level of the directory structure as the AC 9 application.
Can you open "library manager" before AC crashes ?
If you can, I would "remove" from the loaded libraries list in the
right side panel all libraries INSIDE the "Local Libraries folder"
except the AC 9 library, either the extracted or un-extracted form,
you can't have both, and then click "Done".
DO NOT REMOVE "Other objects", FTP Libraries, "Built in Libraries",
or "Objects/Libraries not found".
Please understand I am no expert in library management.
My suggestions are based on my personal experience.
If your setup is different than what I have described above,
then I would not proceed and obtain more expert help.
You might get more response if you posted this issue
in "Installation/New Users".
Peter Devlin