I hate to be the crotchety unpleasable fan, but... I don't like that trailer? Sorry folks. There are plenty of moments from the story that are suitable for jumpscares, but they picked the wrong ones. IT is more than just the monster that jumps out at you, as a very jumpy person, I didn't find this scary. Could do with more 'creeping dread' rather than 'boo!'
Can you really call any of these 'jump' scares by the conventional definition? The whole method of a Jump scare is that we get a silent moment of the mundane, and suddenly your monster/killer jumps out of nowhere. Nightmare on Elm Street 2017 is the king of abusing what should be a tool for tension and release during long stretches.
1. Pennywise in the sewer; That's...just the way the scene works. No matter what, that scene is going to operate on Pennywise being a little unnerving at first. The way it unfolds is that he then backpeddles his creep factor, lures Georgie in with his boat, and then goes for the kill.
2. The ending. The fact is that we're already in fright mode with Ghost Georgie, and we see Penny's face emerging before he blasts out. To me it feels less Jump Scare and more a play out of the J-Horror Sadako/Kaiyako play book. In J-Horror, they have no qualms with showing the monster, and then just piling on by having it go for the throat even though we know its coming.
And to counter that, the projector scene is a real genius move, because it's a dawning realization of dread despite no actualized threat. If you've read the book, you know that Pennywise tries to pop out of a photo album as a 'jump scare' of sorts. Here, it uses the tech of 80s to take something really common place and turn it into an avenue of fear. I almost wish they hadn't shown this scene, since unless you're a stickler for the details, even fans of the book/series won't know what this scene entails until the scene is in full throttle. I've also heard some people say they get a Nightmare on Elm Street vibe off of the trailer. I have to agree, Penny and Freddy have similar meta-magical qualities, and the camera/vibe, even some of the lines feel very similar to Elm Street part III.
So I think besides playing the rules of a trailer, this doesn't seem like a film that's going to rely on jump scares. My only dread is that we know that the sequel is going to be set in modern times. 1989 in this, and 2016 for the sequel. I really hope they resist the urge to go Sinister 2 where Pennywise is on every computer and smartphone screen possible.