The Angel Next Door Spoils Me Rotten Novel Volume 9 is written by Saekisan and illustrated by Hanekoto.

After a fantastic birthday, Amane realizes how much his life has changed for the better thanks to Mahiru. To return the favor, he gets started on preparations to make Mahiru's birthday her happiest yet, and enlists the help of friends, coworkers, and complete strangers alike. In the meantime, impending parent-teacher conferences send waves of anxiety throughout the school. With exam season following shortly after, Amane and Mahiru vow to dedicate themselves to their studies to ensure their future together. Chiefly on Amane's mind, however, is Mahiru's birthday, and the all-important day finally arrives. He has plenty of surprises in store to thrill his girlfriend, but how will she react when he reveals the pièce de résistance?