Version 0.8.9 of kmymoney2 is currently stable (released in march '08). Simply copying the 0.8.8 ebuild to 0.8.9 works fine. I know that version 0.9 (released in may '08) is already in Portage, but that is the development version. The 0.8.9 is currently the best choice for end-users.
Oh by the way, the 0.8.8 ebuild currently applies a patch for a small bug that was fixed in 0.8.9 so no more need for that patch. So simply copying the 0.8.8 ebuild to 0.8.9 is not quite enough, you also need to remove the line where the patch is mentioned. And then it works fine.
Thanks for the report, assigning to maintainers
Created attachment 163606 [details] Diff from kmymoney2-0.8.8.ebuild to kmymoney2-0.8.9.ebuild
Ebuild in CVS.