Common mass market paperbacks run between 250 and 400 words per page, so if you're aiming for the same density of type, 90,000 words would run to around 300 pages, give or take 20% or so.
Manuscripts today don't have to adhere to "standard manuscript format" as was the case for nearly a century, from the invention of the typewriter until e-publishing rose. It's often more sensible to write in the final format you expect your reader to see, if page layout, potential illustration, and such things are important to you.
Carrie was almost certainly submitted to a traditional publisher, on paper, double spaced, Pica type, with minimum one inch margins and a half page white space on the title page and for each chapter break. That formatting was intended to make slush readers' lives easier, by giving a very quick easy reason to reject a manuscript from a clueless new writer, as well as to leave space on the page for markup by an actual editor if it ever reached one. With modern technology, you can potentially bypass all those steps and do everything yourself (or contract out things like copy editing, content editing, proofreader, etc.).
So, comparing to the manuscript for Carrie isn't really sensible -- but if you want to see how your book will look in paperback, you can easily set up your word processor's page layout to match that in a trade or mass market paperback -- page size, proportional fonts, kerning, line justification, as much effort as you want to go through.
My own suggestion is to not worry about it while you're composing; save that part of the job for after the story is done and you're turning the completed story into a book (whether for print or e-publication).