pls which 1 is greater btw certificate and OND Course

An ond is higher, as you can leverage it for admission to study hnd or direct entry into a university.

But you can look at it differently, if what moves you isn't paper qualification rather its the skill set you would attain on completion of any of the above, and it's applicability in the real world, where you need to earn to survive in line with your passion too. This my friend should be your guide