Frankly, 'every' means the same in Rev.5:9 as it does in Jn.3:16, without exception. The result is all kinds of people, but they come from every nation and tribe (without exception)
Calvinists and Arminians agree on this. Every believer in John 3:16 receives eternal life. There is no such thing as "a believing one" who does not receive eternal life. We all agree on this. These believing ones come from every tribe, tongue, nation, and people as demonstrated in rev 5:9. This is the universal nature of the atonement according to Calvinism. I think xzins summarized it well as: "No unbelievers in heaven and no believers in hell."
Calvinists just claim that the Scriptures teach that these believers are the ones drawn by the Father in John 6:35-65 and that unbelievers are not drawn in this same way.
Well, we agree on what the Calvinists are saying, but the verses they appeal to do not say what they want them to say.
Now, does the 'every' in Rev.5:9 refer to all without 'exception' or without 'distinction'?
Clearly, there will not be a tribe or nation that will not have saved people from it, so the pas is without exception, just like it is in Jn.3:16, everyone (without exception) who believes will be saved-period.
That the Calvinists bring theological issues into the verses is exactly what my earlier post from BibleHelp.org was saying.
You are bending the verses to make them mean what your theology dicates it must mean.