Most likely, you're using the wrong output (printer) profile, or none at all.
For the MFC-9450CDN (there is no MDF-9450CDN model), the drivers from Brother install a fair number of profiles. If OS X automatically detected this multi-purpose device and installed its own drivers, then no profiles would have been installed.
If OS X setup this printer, go to Brother's site, download the full drivers for your printer and install them. Just get the Printer Driver download.

Once installed, it will put these profiles into the /Library/Printers/Brother/Profiles/ folder:
broch05_PL_Fi_CMYK.icm
broch05_PL_Fi_IG_OFF.icm
broch05_PL_NM_CMYK.icm
broch05_PL_NM_IG_OFF.icm
broch06_PL_Fi_cmyk.icm
broch06_PL_Fi_IG_ON.icm
broch06_PL_Fi.icm
broch06_PL_NM_cmyk.icm
broch06_PL_NM_IG_ON.icm
broch06_PL_NM.icm
broch08_PL_Fi_IG_ON.icm
broch08_PL_Fi.icm
broch08_PL_NM_IG_ON.icm
broch08_PL_NM.icm
broch10_GL_Fi_IG_ON.icm
broch10_GL_Fi.icm
broch10_GL_NM_IG_ON.icm
broch10_GL_NM.icm
broch10_PL_Fi_IG_ON.icm
broch10_PL_Fi.icm
broch10_PL_NM_IG_ON.icm
broch10_PL_NM.icm
broch12_GL_Fi_IG_ON.icm
broch12_GL_Fi.icm
broch12_GL_NM_IG_ON.icm
broch12_GL_NM.icm
broch12_PL_Fi_IG_ON.icm
broch12_PL_Fi.icm
broch12_PL_NM_IG_ON.icm
broch12_PL_NM.icm
The real problem then is figuring out which of these apply to your model printer; if any. Most were made for plain paper. Those would be any that start with brochxx_PL. Glossy paper profiles are the brochxx_GL items. For instance, profile broch06_PL_NM_IG_ON.icm will appear in your list of profiles choices named as:
Brother/L06A/Plain Paper/Normal/IG=ON
Hmm. Okay, what's that supposed to mean? What's an L06A? What's IG=ON?
Since output profiles are very specific to the model printer they were created on, and the paper used, none of these may be of much help. You'll have to contact Brother and ask which of these are intended for your model printer.