When in Manager Mode wait until the transfer season is open, and instead of spending so much money on the expensive players, go on detailed search, and change it from for sale to free agent.

There you can occasionally find players rated 90 and above.

I got Wayne Rooney, Fernando Torres and Kaka, after 6 seasons, and players rated over 80, I got ten and sold them as each they were worth over 1,000,000.