What I did to get around the Bound Bow being Adept level is to make a second, Light Bound Bow. It is easy, since all you have to do is copy the original spell, effect, enchantment, and item, etc... and make your new versions less powerful. I gave it the same stats as a Hunting Bow, and made conjuring it a Novice spell.
The tricky part is you also have to make new arrows for it as well, because otherwise you will be using arrows with Daedric stats, which is really overpowered at 1st level! Find the Bound Arrow in the Ammo section, copy and rename it, and adjust the damage down (I gave it the same as a Steel Arrow). Then go to your new magic effect for the Bound Light Bow, and in the Scripts box, go to the properties of the BoundBowEffectScript. Select BoundArrow and you can change the object type for it with your new Bound Light Arrow.