Kievan Rus’ ceased to exist in the 13th century when the Mongols invaded so Putin will be reaching way back if he invokes Russian claims on Kiev.
Besides, Moscow has been known as the “third Rome” since the Tatar Yoke was thrown off by Ivan III.
Putin will next be seen wearing the cap of Monomakh & calling himself Batiushka Tsar. He’ll enter the Grand Hall to the chorus of the coronation scene in “Boris Godunov”.