Best way to do contacts back-up(for me!): export all contacts(via inbuilt option "Export to file"), than in /home/user/MyDocs/Contacts run the following command in terminal:
Code:
cat *.vcf > file.vcf
After that file
file.vcf will contain all your contacts. Just put this file in secure location(your USB stick, home PC, dropbox, GMail etc.). You can restore now them in every device/application that supports VCF format(and most of them do!). To restore in your N9 - just find the file in file-browser and click on it.