After one month of successful beta testing, the 1.9.0 major released turned into a fully stable GA release....suitable for production usage.
Feel free to download and torture it - it will proudly do the job for you :) !
Once again, many thanks to all people who got involved in the testing, reporting and fixing during the beta stage - it was a great job:
http://opensips.svn.sourceforge.net/viewvc/opensips/branches/1.9/CREDITS