Even if it is a very soft ball such a a "nerf" ball, my concern is that Cloud could be injured against the side of the playgym or if he was caught between the other balls on the play ground.
I may be overly concerned about safety, but I do believe it is important the Original Poster as well as all members take these matters into consideration when teaching and allowing their precious budgies to do these amazingly wonderful acrobatic feats.
Cloud does look as though he's having a wonderful time.
My thanks to everyone for watching Cloud's video and for your nice comments! Abeyance, frozengirl, BlueBirdNYC, FaeryBee, Bearnoname
Thanks also for your concern. It is indeed a tennis ball. I had seen many videos on YouTube of budgies playing with or balancing on tennis balls and I guess I assumed it was a safe toy for them. Cloud is our family's first bird. We certainly don't want him getting hurt. Do you think playing with the ball on open floor instead of the playground would be ok? Or maybe with a smaller ball? He has another "tennis" ball that is only about the size of a golf ball... but I think his feet are too big to fit on that one!