Testimony Enterprise ltd is owned by a couple who were also charged in the same case besides Kiambu’s first family.
Governor Waititu and his wife are separately accused of dealing with suspect property by paying themselves Sh7,214,000.
The governor's lawyers have opposed the the nine MCAs being enjoined in the case saying it might turn case into a political contest.
A Magistrate Court has directed nine Members of the Kiambu County Assembly to make a formal request to join the graft case in which governor Ferdinand Waititu and his wife are facing prosecution over an irregular Sh588million tender award.
Chief Magistrate Douglas Ogoti gave the directive after the court was told that the nine wanted to join the case individually.
While the defense opposed the move, the magistrate asked the MCA’s to make their request formal as required by law.
“File a formal application showing intention to join this case,” the magistrate said.
According to lawyers representing Mr Waititu, his wife and eight co-accused persons, the request might turn the case into a political matter.
The details emerged during the mention of the case in which the governor is accused of knowingly acquiring an indirect private interest in the contracts awarded to Testimony Enterprises ltd by his county government as shown by payments receipts of Sh 25,624,500.
He allegedly made the irregular payments between July 2, 2018 and March 13.