Taking Walker at 9 would be a complete failure IMO. He needs to have a coaching staff that can really utilize him to the best of his abilities and we don't have that.
If you want a linebacker pick Jihaad. If you want an edge there's much better prospects even at 40 IMO.
MLB at #9, no. Get one later in the draft or in free agency in a year or two, don't like the positional value of that position that high in the first round at all. MLB's are pretty cheap in free agency.