One of the questions in I134 asks for any other person for whom the affidavit was submitted
in the past.

I had filled up and give I134 to my dad almost 9 years ago for his application for visitor visa
application for US. I am not even sure if that time, that affidavit was kept by the embassy (it
was not Moscow embassy, not even in Russia).

Now when I fill up I134 for fiancee, do I also mention that in past I had filled it up for my dad?

any suggestions please.

The question asks if you have previously submitted an affidavit(s) - if the answer is yes (and apparently it is) then you should complete the section.

You can put that stuff in there, complete with your dad's A# and all that. However, if you don't have it, or don't know, I'd leave it out.

They're looking to see if you've sponsored too many people to take care of. If you sponsored your dad way back when, they would probably have to dig through the archives to get that info.

To be safe, I'd list it on there, but if it's in no way connected with this case, you're probably also safe ommitting it.

Better wait for Satellite's input on this one. He's not a lawyer yet, but he's the resident "expert" when it comes to immigration law and paperwork stuff. I'd trust his opinion on this one before my own!

I think you nailed it with your post.
Simply put they are looking to see how many people are tied to your income. So putting down your dad will be like an additional household member. That may or may not make a difference. The second thing they are checking is to see just how many people you have sponsored in the past, kind of looking for fraud, if there is a new "bride" every year or so.
Then again the I-134, though not enforceable probably has some kind of statute of limitations. Your dad, if he returned to Russia or became a US citizen would make the I-134 mute. Although that is not written anywhere, I am just guessing and drawing my information from the I-864, which is the enforceable and better-worded affidavit.
I'd put him down just to be on the safe side.

As for being a lawyer, I'll only finish law school in December, bar in February, and hopefully positive results in May. So it's still a good 10 months before you can seek my services

thanks. My dad does not live with me. He lives in his own country. He has 10 year multiple entry visitor visa for US and just visits me from time to time. He is not dependent on me at all.