replication enabled? If not, I might suspect that you have a large VLF that's active. The log is divided up, and depending on how it was sized and grown, you might have VLFs that are large or small. You must have one active, and if it's large, then you can't clear that VLF until it's filled and the next one becomes active.

Why do you want to get to 1-2% usage? Is there something wrong with 9% usage? I might worry if it were up at 80% usage and I couldn't clear it, but not at that level.