A season number, not just a website name
Doctor Who series 9 usually refers to the 2015 run with Peter Capaldi and Jenna Coleman. Its opening episode is The Magician's Apprentice, dated September 19, 2015 in the official Doctor Who episode record. On this catalog, open the Doctor Who production that began in 2005.
The quickest search
Enter Doctor Who 2005 S9E1. The year selects the production and S9E1 selects the season and episode. The episode guide lets you match a name when a viewing service displays its seasons differently.
Why other Doctor Who pages appear
The classic series and the newer catalog entries are separate records. They can carry the same main title without sharing a season-one starting point. Do not select a ninth season based only on a poster or assume that a more recent starting year contains the 2015 episodes.
Keep your own place
After you finish an episode, save its checkpoint on the 2005 series page. Your saved note belongs to that production and will not advance a different Doctor Who entry. Open Doctor Who and related worlds if you want to compare the available starting points and spin-offs without mixing their numbering.