Hello Esthervdberg
Yes, you can open a project either from S9 or S11 in an avi file. First of all, you need to make an avi from either S9, S10 or S11. Once you have the avi file, close the program and open the version you want to use and follow this steps:
1. Do a project in S9 and make it to an AVI File
2. Close S9 and open S11
3. On you video files in S11 find the AVI file you created open it up and let S11 create the files (or something like that)
4. Now you can start editing or do whatever you need to do on S11
Note: this can also work with this AVI files vice-versa too. Good luck.