Their 3-3 draw with Sheffield Wednesday saw the Rams survive at the expense of the fallen Yorkshire giants.
"No more messing around, it has to happen," said Rooney. "We can't afford to allow this club to be in the position it's been in this season. It needs sorting out as soon as possible.
"It's been frustrating. I'm sure you know I put on a front to keep that away from the players. We can take a step back now and I can say it needs to be sorted."
Concerns remain around a proposed sale to a consortium led by Spanish agent and boxing promoter Erik Alonso.
"We all need clarity, especially the fans," said former Manchester United and Everton captain Rooney. "It needs sorting out as soon as possible. I'm sure it will. We're in a place where it looks like it's happening that way, but it has to happen quickly. We can't have any more mess-ups, no more messing around, it has to happen.
"That allows me to have our plans in place for the Championship next year. I've had a lot of work done: pre-season is done, the fixtures are done, everything is done. But we need everything sorted out from a point of view of the people above me to make sure it allows me to do that job to the best of my ability."