is demon slayer: kimetsu no yaiba episode 9 filler?

It was two demons named Tamayo and Yushiro who came to Tanjiro’s rescue. Using the “Eyeblind” spell, Tamayo guides Tanjiro and Nezuko to her house.

There, through his conversation with Tamayo, Tanjiro learns that there could be a way to return demons to human again. Just then, two demons in pursuit of Tanjiro manage to locate the house, and unleash a furious assault…