The Senator is said to be wanted for alleged homicide he committed in July.
The apex court sitting in Abuja gave the verdict on Monday morning.
The oath of office was administered to the new deputy governor by Justice Nasiru Ajanah, the Chief Judge of the State.
The PDP candidate defeated the incumbent governor who sought a second term in office.
Taraba, traditionally is a PDP state since 1999.
The apex court sitting in Abuja gave the verdict in its ruling on Monday morning.
Mr El-rufai made this known on Wednesday while delivering a keynote address at a colloquium in Ibadan, the Oyo State capital.
Ganduje won with a margin of 8,982 votes.
Meanwhile, Achuba is reported to have proclaimed himself as the authentic deputy governor of the state.
In Zamfara State, mining has been suspended as the area is one of the places where the attacks has risen.