Why won't my MacBook start normally? I have a 2009 MacBook showing world with exclamation when attempting recovery. 

It would not start using regular startup.
This is your computer not having a proper bootable partition on your disk. In simple terms.. It doesn't know where your operating system files are to properly boot.

Sadly, you don't have the network recovery like newer macs do according to several posts like below.

https://discussions.apple.com/thread/4420972?start=0&amp;tstart=0

Your only option is to visit an Apple Store, unless you have a bootable volume (backup, time machine) that you can hold down the left alt-option at boot-up, and then select your time machine. These are configured to have an EFI partitioned on the disk. 

Complex version: 


A disk has a top-level GPT partition stating where "partitions" are on the disk. A partition is a slice of separated files from other partitions. 
Following the GPT map, is the partitions. There should be an EFI partition to tell the system that OS X # is located at xyz on the disk.
The OS X partition.
Then there is a 650mb recovery partition that you boot to to save your system. 


One of these partitions is missing. You didnt say if it would boot normally, only that it wouldn't boot into recovery.