Here's the list of youngsters with a Potential Ability of -10 and -9 by position. (thanks to Jamie) at our FM 2009 players forum.
I am glad my home team's Sotiris Ninis is given a -9, which could make him a wonderkid, and my favourite team's, Barca's Bojan is one of the few forwards to get a -10!Read on at your own risk, as seeing hidden attributes such as PA and CA is practically a football manager cheat!

For those who dont know, -10 means 170-200 out of 200, i.e. guaranteed World Class and -9 is 150-180 out of 200, about a 70% chance of being World Class.

Goal Keepers
-10
Vincenzo Fiorillo – Sampdoria – GK

-9
Josh Lambo – FC Dallas – GK
Antonio Adan – Castilla – GK
Sergio Asenjo – Valladolid – GK
David De Gea – Atletico B – GK
Jose Rafael Alamo – Tapachula – GK
Miguel Angel Fraga – Morelia – GK
Alfonso Blanco – Pachuca – GK
Giorgi Makaridze – Dinamo Tbilisi – GK
Joris Delle – Metz – GK
Zakarie Boucher – Havre – GK
Asmir Begovic – Portsmouth – GK
Joao Carlos – Atletico Paranaense – GK
Oscar Ustari – Getafe – GK
Cassio – PSV – GK
Geoffrey Jourdren – Montpellier – GK
Sergio Arias – Chivas – GK