Yes, but those "classes" can be quite wide, there is for example no way they could trademark it for "Class 9: Computer and software products and electrical and scientific products."
饾晱 is a pre-existing symbol used by, and part of a standard character set for, software. You could probably get a trademark on it for a company selling apples, but I highly doubt you could for a software company.
"used by" is pretty debatable. Its a fairly obscure character. I don't think being in unicode by itself is sufficient enough to count.