Is melee hit cap really 9%?

Here's a good place for you to start, next time. It appears to have applied to all melee/ranged, but not spells.

could you be more specific as in what kind of situations you get misses or is this a general problem?
I can't help but think that you may be exposed to some debuff that lowers your
hit chance as I have not noticed any misses if I'm capped to 8%.

Vault of Archavon comes to mind first.

No. There are no "diminishing returns" from hits at 8% hit and there is no need to be at 9% hit.

Your guildies probably still believe that 9% is the hit cap and that we're telling you 8% because you'll only miss rarely at 8%, hence their use of "diminishing returns". This isn't a correct use of the term "diminishing returns" but is probably what they're referring to. Either way, we're NOT saying that hit is worthless after 8% because you'll only miss rarely, but we are saying that you won't miss EVER unless under the effects of a -Hit debuff at 8%.

Bottom line is that you won't miss at 8% since it is the hit cap.

What your guildies might have noticed is speculation in the Focused aim reducing crit return thread, that the reason we saw lower crit had something to do with hit not being flly realized at 8% concerning crits - I believe I was the one who raised it specifically in those terms. There is, however, no data to back this up at the current time, and other sources are way more likely causes.
IOW, this speculation is not something to base anything on currently.

No the cap is 8%. But there is speculation into Focused Aim lowering crit a bit. It doesn't have to be true though.

Just get 263 Hitrating, and never think of these issues again.

The size of a crit is not affected by hit rating, and you will not get larger crits at 9% hit than you would at 8%. If your hit rating is lower than 8% you will get fewer crits, but the ones you do get will be the same size no matter what your hit rating is.

Though I have to admit that it would be a nice way to make Hit scale past the cap.

If you're below the Hit Cap, either gem/gear for hit or eat +hit food. Its that simple.
Focused Aim should be a last-ditch solution for three reasons. The first is because it doesn't apply to Pet Hit. The second is that there's almost always a talent in reach that will gain you better dps. The third reason is that theres an abundance of well-allocated +Hit gear even at the Heroic gear level.

I'm not sure whether or not your armory's gear is up-to-date since its showing you at 5.31% hit but if you are below the hit cap, do as I said in the first line and either gem/gear for hit or eat +hit food.

I've gone all over this and I've seen results for player hit at just below 8% and just above 8%, but not at exactly 8.00%. Is there any reason we can't assume they're rounding the player hit 'percent' up to next integer? We've proven they're rounding DOWN for the player contribution to the pet. Rounding up for players would fit within the observed stats that have been posted and still fits within the 9% 'official' value (7% + (Defense Skill - Weapon Skill - 10)*.4%). It would also be logical for them to use integer values because they're computationally more efficient. 9% can also be written as 9 out of 100, if you want to use integers

Edit: A more 'sane' thought occurred to me. Instead of rounding UP the hit value before calculating the miss value, they could simply round down the miss value in the final comparison? 9.00 - 8.02 = .98, rounded down to 0. Instead of 9 - 9 = 0 . Either way works and there's no way to prove or disprove either rounding method, but we can statistically prove rounding if we get a sample of attacks at a perfect integer, preferably 8.00 hit.

Sorry, but your theory is not true. If it was, I would have noticed it when I did my testing with 7,99% hit. Over 2k shots I had 0 misses, while your theory would predict 1%.

Screenshot

Still doesn't fit my data. 9-7.99=1.01 rounded down is 1%. And I had these results not only on the above test, but also on the tests I posted earlier in this thread where I only posted the Pet stats. And you can't get exactly 8.00. 262 hit is 7.99 and 263 is 8.01 if I recall correctly.

No... Seeing your number is pretty high though, you can still change a gem or two out of Hit. You only need 263, so if you can drop 12 Hit you are in Perfectland (and gain something in return of course). Chances are that you can only drop 8, but that's fine.

Hit is still a better stat than even Agi. If it wasn't then we wouldn't be going for the Hitcap as Survival, but rather just get whatever Hit there was on the items with the most Agi.