Running Joomla with your CentOS 6 installation without fiddling with base system packages is possible! In short, just enable the SCL repo and use the CGI interface to load the specific PHP version you need.
The expert linux sysadmin can find this tutorial a little over simplified: basic CGI setup can be a little slow, as both CGID and FastCGI/D can give better performance at the cost of slightly more complex setup. Anyway, this is a good start to bring your Joomla 3.3 installation up&running.
Have a nice day!