Anything is possible, but it seems unlikely. even the wikipedia article dismisses the claim that he was the son of sir Thomas Kempe, as the William in their family has a known burial. Had the son of a prominent family turned actor, they would have publicly disowned him. Believe me: I know it from my family. My great-great grandparents came from prominent families (with Magna carta and Plantagenet ancestry). They became actors in the second half of the 19th C and were paid to go to Australia. That was 400 years after good old William. He may have been a descendant of someone else back in the line, though, as family fortunes could plummet for younger sons and illegitimate children.