Val X Love(2015)

Val x Love

Gotta flirt to save the world!! High schooler Takuma Akutsu is terrified of human contact and just wants to live a quite life. Too bad he doesn't have a choice in the matter when nine Valkyrie sisters come barging into his home! They've tasked him with raising their level to fight off the monsters threatening humanity--and how will he do that, exactly...? By gettin' down & dirty to the max!!!

(Source: Yen Press)

Note: Chapter count includes a one-shot from Volume 9.