I have got to say there is no way I can spoil the sheer joy in your heart you will have where, right after Bill gets his closure he’s been seeking the whole movie and It tries to get one last win in, we then move to the kids deny that and then them just taking this downright amazing, epic stand against the thing that has been tormenting them (and you, the viewer, who has likely been scared) this whole movie. What it feels like to see them stand up to the things that scared them, see them help their friends fight It off, see them get confronted with something that earlier in the movie would have terrified them but now makes them scream in primal rage that It would dare try to us that in a cowardly attempt to make them back off.
Just...that scene. That scene. That scene is worth the price of the ticket all on its own, but it gets its beauty mainly through the struggle and terror from earlier in the film. It just feels so amazing and triumphant and you just feel this great release as you watch it, this great cathartic YES and it deserves such praise for that.