No, a Higher Diploma certificate from Olabisi Onabanjo University (OOU) does not typically qualify for direct entry into a BSc program at OOU or other universities in Nigeria. Direct entry usually requires a minimum of a National Diploma (ND) plus a minimum of an upper credit and sometimes, an HND. The Higher Diploma is often considered equivalent to a ND, and is usually not sufficient on its own.
You would likely need to apply through the regular (non-direct entry) admission route after completing your Higher Diploma certificate. You might receive credit for some courses you completed in the Higher Diploma, but it's not a guarantee. Always check the specific admission requirements of the university and department you are applying to.