MMH5.5: Russian Dialogues & Subtitles (All) - This is text for campaigns.
"MMH5.5: Russian Translation (RC8b)" and "MMH5.5: Russian Translation (Alt) (RC8b)" are mod translation. They are the same thing but done by 2 different people. Any of those will work.
You are correct they do not include RC9a changes but since RC8a almost no text was changed. Most of the changes were spell errors.
Translation to other languages is done by other people for free so we don't know if any updates will be released.