If I write my college essay on how much I love the school, will that sound like kissing up?

Most likely. Regardless of whether or not you were sincere, an admissions officer would suspect you were just trying to butter him or her up. Colleges use the essay to learn more about you—so unless that approach reveals what's valuable about you as a person better than any other topic, you should avoid it. However, be sure to take note of why the school is such a great match for you, and make sure that those traits (for example, your interest in a particular area of study or extracurricular) come across clearly somewhere in your application. The committee of course knows what kind of students would be a good fit, and will likely make the connection themselves. If the college doesn't ask you to explain why you want to attend, you may even want to include a supplemental statement in which you rave about them. But choose to focus on yourself for the main essay.