I would also recommend 'An Enchantment of Ravens'. Although it's not solely about werewolves, it has elements that young adults would like in a werewolf - like character within a romantic and magical story. The way the characters interact and the development of the relationships are engaging for young adult readers.
Well, 'Blood and Chocolate' is also suitable for young adults. It explores themes like first love and the challenges of being different in a way that young adults can understand. And 'Moon Called' is a great option too. It has a strong female lead who gets involved in a werewolf - filled world and has some romantic encounters that are both exciting and appropriate for young adults.