Here is one of the combo exercises for save reactions on low and high shots from 9m.
This exercise has many progressions and options, depending on what you want to work on.
It has a fun element to it that is very good when working with young goalkeepers. They love having a “target” / additional task to do (external focus), so picking up the high cone and placing it on the other side of the body always works well when we want to get our young goalkeepers to make a little bit deeper side step for a low save reaction.
Just keep in mind that you should always take care that your goalkeeper is performing proper technique and that you should adjust the level and complexity of the exercise to the level of your goalkeepers.
Besides that, you can be as creative as you want! 🙂
Have fun and let me know how did it go? 🙂