It's natural for a boa to want to hang on to something like a branch.. this is normal healthy behavior. Be patient with the snake and it should get adjusted to being handled - even with all those temtping branches just waiting to be hung onto. The boa will probably really enjoy having something to climb on so it would seem fine to keep them in there. I wouldn't use branches you found outside though unless you treated them somehow to make sure there are no bugs in them. Also remember that anything like pine is not good for boas. some people bake the branches in the oven (carefully) and I have soaked branches in bleach water (I use these branches for some lizards).
If the snake is really hanging on tight to the branches, you might try unwinding the snake from the tail. Hold the body in one hand and with the other hand start uncoiling from the end of the tail. or take the whole branch of and see if it will just come off the branch by itself.. but either way, be patient and know that this behavior is normal..