I feel your pain! That was just like my DS and me a year ago (when DS was 8.5).
I had tried quite a few styles of carrot and stick with my son, and either I wasn't consistent enough, or the approach just fizzled out.
My DH is much more discipline oriented than I am, and I was always nervous about trying his ideas, but finally I decided that it was worth a try. Things we have changed:
1. Work begins right away. After I assign something I check back within 2-3 mins. If DS has started and understands, fine. If he hasn't started, I ask why. Sometimes he needs clarification, and we do that. If he's footdragging I ask him to do some physical exercise, and we begin again in 10 mins. If he procrastinates again, he looses all treats/rights for the day, and he does chores for the rest of the day. I handle whining the same way - I deal with it right away before it starts to grate on my nerves and drive me nuts.
2. I expect more, not less. I had gotten to where I was afraid to assign a whole math WS. I'd ask for 5 - 8 problems (if that's no problem sweetie...). I'd ask for 10 mins of reading, or 2 sentences of writing. Anything more was too much, and I wasn't prepared to handle the whining and complaining normal assignments would elicit. Now he does a math lesson a day (complete with warm ups and extra skills practice), 40 minutes of reading and 20 minutes of writing. Then we do fun stuff. Believe it or not, it takes less time to complete his work now than it did before, and he says he likes "the new school."
I think what really helped was to react right away to the whining and procrastination. I always tried to be super patient and kind and understanding. Unfortunately, I would snap suddenly and yell, or threaten some unenforceable punishment. Now, I'm dealing with issues when I'm still calm and rational. DS knows the consequences. If he flips out and overreacts to the exercise, he's up in his room all day. Things have gotten much better, and we actually get to do the "fun" school (history and science and art) much more now.
-K