That's strange.. but I'd have to assume it deals with something you have present in your save verse being an old save.
Perhaps some items were in places that would be overrode with new objects, and couldn't be purged or moved so it considered the save corrupt.
Most alphas force players to start over every time.
This isn't necessarily the case here - as when I downloaded 9 the first time, I was greeted with my most recent restart save from 0.0.82 which was like day 27 that time around.
This is why I state it must be something specific of your save, and that causes it to not load.
But honestly, you'll probably want to restart anyway.
There's some new areas (no mining I don't think) - And the return of the shield on the pedestal - not sure if it can be sold or what - There's not a "whole lot" of gain from restarting really, but it'll probably feel better
There's,... Some things that will help immediately throw you to the top if you're lucky....
like... Almost giving you the best metals.
I may have talked about this elsewhere...