Like the title says, must I watch the original film, or can Annabelle 2 be watched as a stand-alone movie?
"Annabelle 2" is a prequel, so it is an origin story, and you don't need any prior information.
If you have seen many of the other Blumhouse Productions films, you will notice lots of connections ("Easter Eggs"), including post-credit scenes.
A lot like "Ouijia: Origin of Evil", "Annabelle: Creation" takes a more successful horror-thriller director and does a substantially better prequel to an otherwise forgettable first film.
If you like obvious jump scares and creepy atmosphere and especially if you liked "Lights Out" or "Ouijia: Origin of Evil", go see "Annabelle: Creation" for sure.
The only reason you will "need" to see "Annabelle" first, is to fully understand the post-credits sequence -- but it's pretty obvious without seeing the original movie.