If you absolutely must open your Sony a99 Mark II files in Lightroom today then you can use exiftool to trick Lightroom into thinking your camera is a Sony a7RII with the below command.
exiftool -SonyModelID=”ILCE-7RM2″ *.arw
I am not going to link you to the tool, because it is a command line tool and could be a bit advanced for some users, but if you’re interested in giving it a try I have received reports that it works.