What does it mean when people say the wicket keeper is coming up too early to spinners and what drills can help keepers?

Hi Mark,keepers should be trying to stay low and come up with the ball as it bounces. Almost like you’re coming under the ball. Watch the ball and react to what the ball does not what you think it may do.
• any drills you do work on technique.
• quality not quantity
• short catches 1m apart, eyes level, feet shoulder width apart,using your legs to drive you up , not bending from your back.
• longer catches pretty much the same.
Hands out in front , give with the ball.
Try to catch ball on your inside hip using fast feet to get into position.
• or simply get a stump and get someone to throw balls at you with and with out a shadow batter( someone who means to miss them.
Plenty more drills … try Utube
Hope this helps mate good luck
Ps .. remember you’re going to make mistakes. It’s ok👍🏼