Netflix makes a selected number of original documentaries available for one-time educational screenings. To find out which titles are available for educational screenings, go to the "All Alphabetical" section of Netflix Originals and look at the full entry for the film you are interested in. If the film is available for educational screening, the Grant of Permission for Educational Screenings will be right on the listing (see Audrie & Daisy for an example). Permission to screen the film for educational use stipulates that the film must be accessed via the Netflix service, and may be done one time only.* Because the one-time educational screenings are just that, one-time, there is no way to make the film available on demand.
In general, though, Netflix cannot be used in the classroom because Netflix subscribers are bound by their Terms of Use, which explicitly state that viewing is for is for “personal” use only and “You agree not to use the service for public performances.” So, even though there might be a classroom exception in copyright law, the license (and your agreement to it) will likely prevail over the law.
*one-time screening means that you can't hold screenings several times in one day or one week - but if, for example, you're an educator who wants to show the film once a semester over multiple semesters, that's okay
Answer: Probably not
Hulu offers only individual subscriptions. Section 3.2 of the Hulu Terms of Use states:
Hulu is pleased to grant you a non-exclusive limited license to use the Services, including accessing and viewing the Content on a streaming-only basis through the Video Player, for personal, non-commercial purposes as set forth in these Terms.
Although classroom use would be non-commercial, it would likely not be classified as personal use. The license (and your agreement to it) will likely prevail over a classroom exception in copyright law.
Answer: Probably Not
Amazon Prime offers only individual subscriptions. Section 4h of the Amazon Prime Video Terms of Use states:
Subject to payment of any charges to rent, purchase, or access Digital Content, and your compliance with all terms of this Agreement, Amazon grants you a [...] limited license, during the applicable Viewing Period, to access and view the Digital Content in accordance with the Usage Rules, for personal, non-commercial, private use.
Although classroom use would be non-commercial, it would likely not be classified as personal use. The license (and your agreement to it) will likely prevail over a classroom exception in copyright law.