In two words BABY EINSTEIN!!! I'll explain this soon but firstly...
I have a very active 8mth old boy who used to be like your bubs. I think with age and a bit of luck thrown my way (for once with him) he is playing on his own longer now. When he was at his worst I had to pick him up as not even sitting with him whilst he played was enough.
I had heard about Baby Einstein DVD's and a friend of mine who had twins highly recommended the water DVD 'Baby Neptune', after she saw how ratty Connor was. She had it and her twins would sit silently for the 25mins DVD. She could confidently go for a shower, leave her twins etc.. knowing they wouldn't move a muscle.
It took three plays and Connor was hooked. So now I let him play until he is getting bored and agitated then I whack on a DVD (as I own the lot of them now, they are my at home baby sitters) and he sits content and mesmerized by the TV. It also teaches him things and has nice classical music behind them so they aren't annoying for Mum either - quite relaxing in fact.
Try them, you won't be disappointed. Connor has been watching the Baby Neptune one since he was 4.5months old even though it's recommended for 9+ months.
Big W sell them for only $15-$16 now, or you can borrow them from your library.
Good luck and let me know how you go.