There are three first league manufacturers, LG, Samsung and Panasonic/Sanyo. Last time I looked, the highest capacity 18650 any of them made was 3,600 mAh, and they weren't easy to find. They all make 3,500 mAh 18650s.
You can take claims of anything over 3,600 mAh, as nonsense.
From what I've seen, the supposed 9,900 mAh cells are recovered from old laptop battery packs and relabeled. You'd be lucky to find they had a 1,000 mAh capacity - most can't manage that.
There are a few Youtube videos on this.