In the section "Description" DBIx::Class calls itself an SQL to OO mapper with an object API inspired by Class::DBI, the latter, according to its introduction, provides a convenient abstraction layer to a database. This description seems like a good match to me.

On the other hand, I am not aware of test suite which a product must pass to be called an ORM, and of course, the truth is available on the internet. List of object–relational mapping software lists DBIx::Class as the only Perl ORM (whereas Ovid once collected about 30 for a talk), and the module even has its own (lousy) entry.

So, well, it can't be wrong to call DBIx::Class an ORM.