They all go thru this, and it's not disobedience, it's just play to them. It's getting them to understand without crushing this playful spirit that is the challenge.
Gracie understood early on what I wanted when I said Come Here. If she did the whole backing away thing as soon as I tried to pick her up, I'd just turn my back on her until she came around to the front of me. I'd say Good Girl, Come Here, reach down for her if she'd back away again I'd turn my back on her. I wouldn't play the game. After only a time or two she'd figure it out, she doesn't like being ignored.
The toy thing is more annoying to my DH then me. The way I see it is if she is bringing me a toy wanting me to play with her and the game she wants to play is Keep Away, then ok, we'll play Keep Away. She taught herself to fetch, she'd bring the toy and drop it at my feet, I'd throw it, she'd get it and bring it back. When she wants to play fetch, then we do. When she wants to play Keep Away, we do.
Pick your battles, playing Keep Away with a toy is purely a game to them and they aren't doing it to be mean. They are little stinkers and they can have quite the mischievous look on their faces when the play, but there's no malice involved. The Come Here command is simply one you need to work on so that they'll understand it's not a game, but something they must obey. He'll get it, he's only 8 months old and is still testing his boundaries. Just be firm and fair, he'll figure it out.