Oh My Wizard by Hadena James

Soleil Burns was born to be an exorcist. Since meeting Valerie and Jerome Dusdain, the previous summer, her life has been chaos, good chaos, but chaos. Soleil has started her own private exorcism company, in preparation of becoming the guardian of the most powerful wizard in the world, who also happens to be only fourteen years old. With Valerie's cancer getting worse and the archangel Michael's dire warnings regarding her impending death, the possibility of becoming Jerome's guardians is now more of an eventuality.

While helping Jerome with his homework, Soleil notices her normally energetic werewolf neighbors aren't up and around like usual. Then she notices they have a package on their doorstep, which is strange since it's a Sunday. When she goes to check on them, she finds the house full of silver particles and the five werewolves barely clinging to life.

Soon, she finds herself chasing a serial killer. A serial killer who knows her every move. She must stop him...