I think not.
Latino-Review, usually a rumor mill that tends to get things right (especially when it comes to upcoming Marvel films), apparently got word that Pixar was "given" their chance to make a Star Wars animated feature…
I think this is not going to happen, regardless of the fact that Pixar was once a division of Lucasfilm.
Up until now, Pixar has made nothing but original films that aren't based on any pre-existing material. No novel adaptations or anything. In fact, when Disney bought Marvel back in 2009, it was speculated that Pixar would make an animated Marvel film, perhaps something like a Doctor Strange film. But they didn't, and they currently have no plans to make an animated Marvel feature. Walt Disney Animation Studios on the other hand, given the fact that a majority of their animated library is adapted from different stories, will be making a Marvel film. It's called Big Hero 6 and it comes out in November.
Pixar's release slate currently stops at the summer of 2018. Inside Out and The Good Dinosaur come out in 2015, Finding Dory will follow in 2016. There are two currently untitled films scheduled for release in 2017, and another one the following year. Prior to the announcement of this tentative slate (this was back in May), there were other projects that were announced that did not have release dates or titles. Lee Unkrich's Day of the Dead film should come out after Finding Dory, which will make it Pixar's June 2017 release. Teddy Newton - director of Day & Night - has a film in the works that will penned by Safety Not Guaranteed scribe Derek Connolly. Mark Andrews has something of his own in the works, though I doubt it's a Star Wars film. Then there's also canceled project Newt and supposedly another sequel, going by what Bob Iger said a while back about upcoming Pixar films.
Unkrich's film, Newton's film and Andrew's film fill the 2017 and 2018 slots, or the potential sequel or Newt. The earliest a Pixar Star Wars film will open is in 2019 or 2020.
If anything, Pixar's Brain Trust probably took a look at the script for Star Wars: Episode VII recently. After all, they took a look at the scripts for films like TRON: Legacy and The Muppets, adding things. Since the Episode VII script was confirmed to be complete and ready a couple days ago, it's possible that someone at Latino-Review found out about Pixar (possibly) working on the script for the film, and then getting "They're making a Star Wars film!" out of it.
Or Pixar might be producing animation for Lucasfilm. Maybe they are crafting a logo for them, or FX for some project, or maybe helping out with something else.
But I firmly believe - until we get an official confirmation - that Pixar is not going to make a Star Wars film. Money-wise, it's a no-brainer, but Disney has been pretty hands-off for the most part when it comes to Pixar (except Cars 2), plus… Why? What kind of Star Wars movie could Pixar possibly make that has nothing to do with the main series or any of the TV shows?
Color me shocked if it turns out to be true…