There are a few things that seem to point against Credence being a Dumbledore. It's not yet completely ruled out he is, but it is also possible Grindelwald lied, and given the circumstances, that can definitely not be ruled out.
WARNING: THIS MEME CONTAINS A SPOILER FROM FANTASTIC BEASTS: THE CRIMES OF GRINDELWALD. IF YOU HAVE NEVER SEEN IT, KEEP SCROLLING. YOU HAVE BEEN WARNED! US WATCHING CRIMES OF GRINDELWALD; CREDENCE IS AURELIUS DUMBLEDORE; US
