While we don't get a ton of information from the text about what characters are thinking or feeling, we are told straight up that the wild things are frightened by Max (27) and that Max feels lonely when the wild rumpus ends (36). So the narrator clearly knows what's going on in the characters' hearts and minds. And since we're told these things by a sort of fly-on-the-wall observer, we know we're dealing with a third-person omniscient narrator, even if that narrator doesn't seem to be offering up a lot of intel.
But if we really want to talk point of view in Where the Wild Things Are, we should talk pictures. And when we look at the pictures—which are also part of the narrative voice—there's no doubt of our narrator's omniscience. And there's a lot of emotion on display.
Max's feelings are so clearly communicated by his facial expressions from one illustration to the next that we could create an emotions chart by cutting and pasting the 30-odd images of him into a Brady Bunch-style grid. And the wild things? And Max's terrier? Yep. We can tell what they're all thinking, too. href="https:> href="https:>