While it was originally slated to have 10 episodes, after the COVID-19 pandemic came into play, the final episode needed to be pushed. “We had to push an episode into Season 2,” executive producer Brad Winderbaum explained to Collider. “It was just, honestly, like everything else, that was a COVID impact. There was an episode that just wouldn’t hit the completion date, but luckily we do get to see it in the second season of the show.”
Although What If…? won’t deliver the full 10 episodes many of us expected, it’s been confirmed for a Season 2, so we can’t complain too much. Brad revealed that Season 2 will also have nine episodes, so there will be a total of 18 episodes of What If…?
But that doesn’t mean there won’t also be a Season 3, if all goes well!
Source : https://www.distractify.com/p/what-if-release-date-episode-count