Wow, I really tried to make your life miserable, but you seem to have found some nice solutions. Good job

I'd probably do something like this:
1. 6 has a narrow opening, shoot it in the corner
2. Shoot as strong as I could at 4 to direct 3 in the direction of 1. One of them has to drop, and I most likely kicked 8 away from the pocket, so it's one bullet two (or more) kills

3. I'd go after 5 next, and by the time I pocket it, 7 or 2 should be open
4. Drop 2 and 7 (hopefully without much trouble)
5. Finish whatever's left
6. Play smart on 8, and if everything went according to plan, by the time I pocket it, the opponent won't even clean out their own balls