I don't think it really needs a certification, maybe do project management? I was doing SCRUM / XP for years before I knew what they actually called it
Our SCRUMs kinda evolved into standup meetings. There was an initiative to switch to KANBAN (or whatever it is called from..the one Toyota uses) but that never really took off. Strange.
Any way, I've never really heard of anyone with accreditation for being a SCRUM master.
Its a requirement at some orginisations, some companies are really into it... the client I'm currently at has every single team doing it, the various application development teams, report teams, back end teams, bi teams....
On a serious note though youtube it there is amazing how to videos and pointers to get a feel for it.
You don't HAVE to go for formal training there is a lot of material on the web to get you going.
I plan on doing my certification next year January after my OCP.