If we land at #9 it means we've gone at least 6-5, and Cleveland goes winless for the rest of the year (or we've at least caught the Pistons, and another team who picks 9 or worse gets VERY lucky in the lottery. Neither of those are likely). We're not picking at #9. Likely no worse than #7, and probably better than that. There's not enough time to make up much ground, especially with Rondo sitting 3 more games.
If we land at #20, the Nets will have somehow passed Chicago and Toronto, two teams that they trail by 2.5 with 11 games to go. Not impossible, but pretty unlikely that they pass even one, much less both (although since our next 3 games are against Toronto and Chicago, this scenario at least jibes well with the scenario in which we win a lot of games an pick 9th). They're more likely to give us pick #17 than #20, honestly.