Should I list an activity that I did for a long time, but only one year of high school?

I played piano for around 8 years, but I lost interest after 9th grade. I have some fairly decent accomplishments though, including playing at senior homes and being in a band for a year. I feel like I should include this, and it did mean a lot to me. Should I put it on the application even though I only did it for one year of HS?

Depends how much space you have and how many other activities. It’s perfectly valid, but would probably fall down the list based on what you described.

If it was that important to you, you would still be doing it, right? Use it as a reference to shine some light on it, in your essay. Colleges want to see activities for 2-4 years to show commitment and dedication. So “even though in 9th grade I enjoyed playing piano music at the senior home on Wednesday’s, for the last few years I have been doing X”, kinda thing.