The engine in the CT had a revision in 2014/15 to stop carbon build up on the piston rings which could ultimately lead to oil consumption and engine damage. I'd therefore state for your vehicle that the standard 10k/12 month service interval is fine, provided you use quality oil, but no harm in changing more frequently (other than environmental).
Toyota/Lexus use the same oil in the US, it is just that the market there expects more frequent oil changes (or more precisely, there isn't the same pressure to extend the services intervals as there is in Europe).