According to Variety , Lucasfilm is in early development on a solo Obi-Wan Kenobi film. A Obi-Wan film has been long rumored, and given the long stretch of time between Revenge of the Sith and A New Hope, there are a lot of stories that can still be told about old Ben Kenobi. While there has not been a writer attached yet, director Stephen Daldry (Billy Elliott, The Hours) will supposedly be helming the film.
There has been no mention of whether or not Ewan McGregor would come back to the franchise, but given how vocal McGregor has been about returning to the role, and given how much the fan base wants to see him return, Disney would be foolish to recast. McGregor lent his voice as Obi-Wan briefly for The Force Awakens, so clearly the door is still open on both sides for his return.