I've had this issue since it came out and never considered it to be a Wildchild appearance, but Comic Vine lists it as such so I had a flick through and the only page I can think they mean is this one, at Sabretooth's funeral;

Click image for larger version.  Name: WTE1..jpg  Views: 68  Size: 678.7 KB  ID: 578

Now, the very much Sabretooth-esque one appears to be way too large to be Kyle, but it is an alternate future so who knows.
The only other option is the purple Nosferatu-esque character next to Mystique who could be a very mutated version of the Weapon X Kyle.
Or, it could be none of the two and the website are simply reading too much into it.

Any thoughts?