I think you should use it, and accept that some people won't be able to run your game. I would make it very clear in the readme, and maybe even do a version check in your game that aborts with a helpful error message if pygame.version.vernum[:2] != (1, 9).
i've used it before and never had any problems with it. i highly doubt anyone will be using a version of pygame older than 1.9.2, so you should be just fine. afaik, the 'experimental' nature of the module is just the api. it is very stable in use.