If someone get a bad preformance review and then claims they have a disability but never reported it to HR during the time of the performance review, can they still claim they have a disability, that is why their performance suffered. Shouldn't it have been documented during the same calendar year as the review period?

Really the disability has no real value. Even when notified, the employer only has to make accommodation if it is cost effective But you have the obligation to notify them.

A good company may consider, but if the disability is so minor, the work place can not notice it,?

But the worker can talk to HR about it.

If you want to use the disability as an excuse for bad performance or to get some sort of accommodation from your employer, of course you would have to prove it.

The employee should have reported the issue as soon as it started to affect performance. Not doing so means the employer does not have to consider the problem.