If you got to the Export Your Season 1 Save screen at the end of Season 1 (right after the end "End of Chapter 8" screen), you can just hit the Import Save button on the Season 2 menu.
Oh sorry, my bad. Well 10 isn't out yet, but when it does come out you should just be able to delete your old version, download the new version and it should be good to go. Renpy games store their save files separately on your system somewhere so you can freely delete old versions, reinstall new ones etc... and your saves should be there still.