The new RCCDroid Android App (Download here at play.google.com) now added support for the Sony A99! This is the description of what you can do:
Remote Camera Control for Sony SLT-A58/A99 over USB, to replace Sony RM-VPR1
– Tethering A58/A99 (an OTG adapter must be connected to the android device)
– Contactfree shots
– Contactfree BULB
– Preview of taken pictures
– Display of camera parameters
It is planned to implement the following features:
– Change of camera parameters
– HDR-shots with different values
– Timer-shots
– Video-shots