Hello and welcome to the family, Harro, glad you could join us and congrats on your new grey, please let us know what you do name him.
Please read thru the many threads here on various topics for lots of useful information and if you have specific questions, as you already have asked, we will do our best to get you an answer and help you in any way we can.
In answer to the clipping wings question, sounds like he may have been too severly clipped, he should not be falling like a rock, he can hurt himself that way. He should be able to glide to the floor but no he will not hover at all.
Do not show any fear or hesitation on trying to get him to step up, he will sense that and act on it.
As far as getting him back into the cage, just put him there, he needs to know that he has to go back when you say so for you are the boss, he will eventually learn that he goes back when you say so.
I would try taking him into the shower with you and see how he reacts, some greys do love to bathe and take showers, you won't know unless you try.
If you have a picture you would like to share with us, we would love to see him.