No, Pluto is not being reinstated as one of the planets in our solar system but scientists are examining evidence that indicates a possiblity of the existence of Planet Nine. The definition of a planet is simply "a celestial body orbiting the sun, big enough for its gravity to make it round, and has dominated the surrounding objects in its neighborhood. Pluto did not satisfy the third requirement and so it was demoted to a dwarf planet. However, scientists are convinced that there is an object large enough to influence other objects around it with its gravitational field.
(Image credit: James Tuttle Keane/Caltech)