Will I Have to Wait for my Braces to Come off Before I Can Get a Crown on a Molar?

I would wait to get a permanent crown once your braces are completed.  Attaching a bracket to porcelain is much more difficult than to either a tooth or temporary crown.  I agree with the opinions you already received.

I would wait until ortho is done before getting into that.  If the molar has a band on it for braces, it should be ok with the filling that was placed following the root canal.  The bite and contacts will keep changing with braces so from alot of angles it's better to wait.

You should have a very good temporary crown placed on the root-canal molar, and have it removed and recemented every 3-6 months while you complete your ortho. It's best to wait for the permanent crown until your teeth are in their final position.

If the tooth is extremely fragile usually the additional retention like post inside of the canals are added. Once placed inside of the tooth, with adequate core material and composite restoration - it will prevent tooth from breaking. In case when the dentist recommends to place a temporary crown - it can be an issue with bonding the braces and dislocation of the crown.