"hit the bookstore" means to visit the bookstore.
Does it make sense? No. After all this time, are you still expecting the language to make sense? It's not an especially common expression, but you see 'hit the . . .' fairly often.
If you are going to a bank or liquor store, Do Not say you are going to hit the bank or liquor store. People might well think you're planning a robbery.
Don't give up, but at least consider the context. And don't tell your friend he is wrong.