I'd say so, yes. A pianist, to me, is someone who has learned how to play very well, but anyone can "play the piano", even if they just barely manage to play "Mary had a little lamb."
Although I would still only use the expression "to play the piano" if someone is actively doing it, like following a course, or doing it on a weekly basis, trying to get better at it. Or if they already know the basics but haven't played in a while.
I followed piano lessons many years ago. Although I haven't touched a piano in at least a year, I would say that I "play the piano", but I am certainly not a pianist.