I had the very same thing happen with my room and a family of Huntsman Spiderlings.

My approach was to just cover the shelves with sheets, basically everything you want covered - cover with sheets

and
Bomb the room.

You may have to avoid using the room for a couple of hours or a day, but it'll do the trick.
I felt sad and bad when I had to do it, cause personally I love spiders - I don't like not knowing where they are though and my room isn't the safest place to be.
*Edit: Not sure if this'll help but I've got 10ft ceilings, thought I might add that.
