There are a lot of bluetooth and wifi obd adapters but only a handful of them(e.g blurdriver) claim that they can read and clear abs and srs codes, so I'm wondering whether a cheap elm327 based adapter can deal with srs and abs modules?
Most "cheap" or "universal" type code readers are only going to be able to do things that are exposed as OBDII parameters. The car manufacturers are free to do whatever else they want using whatever proprietary protocols they want.
Air bags are not a part of the OBDII spec, and thus requires a special reader. Some readers might have the right protocols and may be able to read the airbag codes, but even then they might not be able to clear the code for technical or liability reasons.
Also, there's not a huge demand for a device that can do this because the airbag and SRS systems normally require other special tools that are out of reach for most do-it-yourselfers. They are critically important and delicate systems.