The Oracle Solaris 9 operating system is now in the Sustaining Support period of it's life cycle as of October2014. Customers with support contracts can still access patches and log new service requests.
Support terms are laid out in the Oracle Hardware and Systems Support Policies (PDF) document.
Oracle Solaris life cycle information can be found at the Oracle Lifetime Support Policies page. The policies that apply to Oracle Solaris are found in the Oracle Lifetime Support Policy: Oracle and Sun System Software (PDF) brochure.
Oracle Solaris Legacy Containers are a popular migration method for moving Oracle Solaris 9 applications to newer hardware running Oracle Solaris 10. See the following two white papers for more information:
Of course the best option is to fully move over to Solaris 11 if the workload allows for this.