How do I get 8 or 9 star players?

[Bunzo]

I haven´t seen any full squads of 9 star players in 20 seasons of playing.I have seen a few with 9 or so players @9 stars but they are manipulating the loan function in Associations (another story)
I have a 138% team just now with ten 8 star players all under 22 years old but i´ve started to gather some 18-19 year olds ( 7 stars)to replace them as by the time they reach 24 it takes too many green packs to keep them at 8 stars.If you have the right players from 18 years old you should be able to keep them at 8 stars for 4 or 5 seasons easy with the training.