But couldn't you say that about every position? Who at u9 or u10 has mastered their position? At u9 or u10 there is so much to learn at every position and one kid who is elite at that level could be extinct 5 years later, way too many factors to consider.
I think you can only look at what is comparable...what is the top level goalkeeper look like at u9 and u10 and are they above their peers? There are going to be some that are better, and some that aren't, but trying to identify a gk as being elite because of a certain skill set is ridiculous. You have to look at them comparable to world class and see where they rank. An elite player, is an elite player, because they have more skills than someone at that same age...if you are trying to identify an elite player based solely on a skill set you will come up short, especially in the younger ages.
There are certain basic skills a goalkeeper has to master at the basic levels. They include: catching, diving, distribution, playing with the feet, stance, and positional play. I'm excluding here higher level stuff like tipping over bar or extension diving. This is the basics. At age 10, their bodies simply aren't wired to do it and they don't have enough training to successfully execute it. Yes, you can have a superathletic kid that does a good job at one particular aspect of the play....that doesn't make him elite because they don't have the training. A reputable GK trainer won't even start training a GK before age 8/9...there's no point....they can't safely execute the very basics of the moves without hurting themselves. And at U10 the expectation really should just be try and block the stuff that's shot right at you.