Maybe one of the reasons why you can't upgrade youth facilities, is that because Chairperson (maybe yours as well?) has it's own youth importance. From manual:
Working with Youngsters
This reflects how successful a coach is at working with younger players – those aged 19 and under in particular. A non-player with a high rating here will improve the players they work with if given a youth team training assignment, while the quality of an annual youth intake is affected by the rating of the person responsible for bringing them through. It is also used to determine an individual’s interest in young footballers overall, such as the Chairperson when asking the Board for improved youth facilities.
No upgrade option for youth facilities
in Player Development, Injuries, Finances and Training
Posted
Edited chairman work with youngsters rating and the option appeared.