No, the void dragon for all of his hatred, would never lie about something, literally only he, his family, or the rest of those who fought in the War in Heaven, would lie about. It would be the equivalent to a Sentinet Dinosaur being found alive in a block of ice, being sentient, and then telling the humans who found him, mice that might be related to them ate bark and sap.
Nothing in anyway shape, or form, has ever said that psykers were made thanks to the Old ones, or anything on any such levels, manipulating the psychic powers of the human race.
The only thing close to that, would be with The Emperor, and most of that idea, Is A Fucking Theory!