Cyrion's Home is the home of Cyrion Tabris and the City ElfWarden. The City Elf Warden will wake up here on the morning of their wedding day.
If the Warden is not a City Elf Cyrion's home will first be opened during the Unrest in the Alienage quest. When entered, the Warden can see Soris standing next to the fireplace if he was rescued. The Warden is greeted and thanked for the help Soris was given.
Bug! After completing quest 'Unrest in the Alienage', talking to Soris and choosing any dialogue along the lines of 'Can you tell me about what's going on here?' will reset the 'Unrest in the Alienage' quest -- as will letting him mention the plague. However, you cannot complete the quest again.
It is best not to engage in dialogue with him, to avoid this problem. Or choose the dialogue options 'I don't need a reward.' and then 'I should go.', if you wish to speak with him.