In a recent interview with TV Guide, Smallville executive producer Brian Peterson said:
"I would say we will see members of the future Justice League who we haven’t seen in a while. They will appear in the Justice Society episode and in the back section of the season. I can’t confirm who you will see, a lot of it is cast dependent. But we do have plans to have a few more members of the future JLA back on the show."
Peterson also spoke about the direction that the potential 10th season of 'Smallville' would take.
"I think our plan right now is a reflection over the 9 years and taking him out of the darkness that we’ve had, with him in the black suit and where he went after Jimmy’s death, and taking him to a place of balancing his Kryptonian side and his human side,"
"It would be him learning how to be Clark Kent and the entity that will be known as Superman.