"I think, you know certainly, for next year, everyone is going to be back... absolutely," said Cowell during a Tuesday morning appearance on The Ellen DeGeneres Show.
Fox reality chief Mike Darnell has previously stated that he doesn't foresee any changes to Idol's four judging panel for next spring's ninth season, but there has been some uncertainty since Paula Abdul's contract expires at the end of the year and new fourth judge Kara DioGuardi is on a one-year deal.
While Cowell has previously stated he would "fight" for the jobs of Abdul and Randy Jackson but failed to mention DioGuardi, he told DeGeneres he now thinks Idol's new four-person judging panel works well.
"The advantages outweigh the disadvantages," he told DeGeneres. "I've gotten to know Kara now and I like her. She's cute."
Cowell also coyly addressed his own contract, which will expire after Idol's ninth season along with that of Jackson.
"It's been the best eight or nine years of my life. I've had the best time. There's nothing to complain about. We've all gotten along really well," he said. "I just believe sometimes everything has to come to an end."
As for Idol's Top 4 eighth-season finalists, Cowell said he's now unsure who the favorite is after he previously stated Adam Lambert and Danny Gokey were front runners.
"If you'd have asked me two weeks ago, I would have said 100% Adam and Danny," said Cowell. "But then last week something unusual happened -- they were all good. Seriously good. What I really liked about it was I really felt an effort from all of them."
Cowell added that he thinks having a winning attitude is important, and he suspects home viewers feel the same way.
"I think it's important for the audience at home to see people competing. That's what I saw last week," he told DeGeneres. "I think it's made it very exciting. Genuinely, at this point now, any of these guys -- or the girl -- could win... It's terrific at this stage that it's so open."
Specifically, Cowell said he's recently been impressed by 17-year-old Allison Iraheta.
"I think she finds it difficult to communicate. She's quite shy and awkward," he said. "Once she can get a bit of her personality over, she's got a shot."
However Cowell said Lambert is still his choice for most-likely eighth-season champ based on "originality" and "worldwide appeal."
"I like the fact that he's fearless. He's not playing it safe," said Cowell about Lambert. "He's got guts."