Noragami Omnibus 3 (Vol. 7-9) : Stray God

Yato has a fateful encounter with Hiyori, a human who tries to save him from getting run over by a bus. Hiyori is hit by the bus, but somehow avoids serious injury. Further, it seems she's undergone a strange change where she can remove her spirit from her corporeal body. Yato seems somehow involved or responsible for Hiyori's change. Could Hiyori be the divine weapon that Yato needs? Includes volumes 7-9.