I'm pretty new into Eternum too, finished it 2 days ago but the logical option is simply to copy the game save and then replace it with the new version.
0.9 version is in around 80% done, almost 2 weeks ago was update reporting a work status of 74% (around 6% per 2 weeks at the moment) Assuming that the author's work goes just as smoothly, We can expect that the public version 0.9 will be ready by around mid-December.
