The 'Juniors' used in Biafra, as far as I recall, were much modified with strengthened airframe, high mounted tailplane, more powerful engine, and underwing hardpoints for weaponry. I think they were designated MFI-15 rather than MFI-9.
The aircraft used in Biafra were MFI-9, built in Sweden (MFI = Malmö Flygindustri). I think Bölkow made some modifications to it before producing under licence as the Bo 208 Junior.
The MFI-15/-17 was a later development with essentially only the looks in common with the MFI-9. Amongst others, it's bigger, has a more powerful engine (200 hp), a T-tail and two single sticks. It was produced in series by SAAB and is in use with the Danish (had a flight in one many years ago...
), Norwegian and Pakistani Air Forces (where it was also manufactured locally). There are a few civilian examples around, including a neat "experimental" example currently on sale on planecheck.com