THR says there will be a new writer, but Lucasfilm isn’t naming anyone just yet. Whatever the case, this doesn’t appear to be quite as dramatic as what we saw with Michael Arndt* and Episode VII, and the new writer may very well just be tweaking Whitta’s script.
I don’t expect we’ll hear anything definitive until/if Lucasfilm chooses to give us their crew breakdown, assuming they follow a similar template to The Force Awakens‘ announcements… Though at this point, I’m not expecting anything until they actually begin filming. That’s expected to happen in a matter of months, given the December 16, 2016 release date.
* Granted, Michael Arndt was not on Twitter. Whitta is pretty awesome at it, Star Wars or no Star Wars.