After long searching for a way to pass arrays as parameters, the closest thing to a solution people recommended was implementing a UserType for them and even had examples of such. They were supposed to be loaded through the xml configuration, so I after I did that I discovered that the data is never entered into the map that is looked-up for the types when calling setParameter().
Wrote 40 lines of code in Configuration.buildSessionFactory and I made it work. Tested it in the company project and got the desired results from the PostgreSQL query "SELECT * FROM my_table WHERE id = ANY(:boo)" . It doesn't work with "id IN :boo" or with positional parameters like "id = ANY", but that can be smoothed-out later if you agree with the idea at large.
This is no longer relevant since MetadataBuilder.applyBasicType(UserType type, String... keys) allows you to register a UserType during bootstrap.