I went through several "replacement" parts with the HID kit I purchased, none of which fixed the issues I was having (flickering/light shifting, light shutting off after a few minutes of being on, etc). I just didn't trust that the lights would work reliably enough for use in a primary vehicle for me. That's why I returned the kit and got the H9's instead.
As for the H9B, I like the idea a lot, but availability and price hindered my choice. From what I found, there is only one place to order the H9B
from, and it would cost $68.81 for two bulbs with shipping. The H9's I purchased were $20 for two shipped. In a pinch, most autoparts stores also carry the H9 bulbs as well.
The cut-off line is the same, there is just more "spill" and a brighter hot-spot. No "unwanted" light or glare. I just put them in last night, so I will try driving around more with them soon to get a better feel.
Putting an H9 bulb in a reflector H11/H11B housing is not generally recommended, however, with a projector beam application, it is just fine. Not having the cap/cover on the end of the bulb does not affect the beam negatively, due to the design of the projector housing. If you search other car forums, the H11 to H9 swap is a very commonplace thing to do. In my case, I didn't even need to modify the bulb base with tin snips as some forums suggest (trimming the metal tab to fit easier into the holder), it just fit in no problem.