Why does my environment require I run bundle exec?

As @lucapette said, you probably have multiple versions of rake. Assuming you do want to use 0.9.2 you can remove the 0.9.2.2 version to get rid of the warning then run bundle install to ensure you have all the right gem versions for the version you do want (0.9.2 in your case, 0.8.7 in the my example below).

Here are the steps:

$ gem list

*** LOCAL GEMS ***

...
rake (0.9.2.2, 0.8.7)
...

$ gem uninstall rake

Select gem to uninstall:
 1. rake-0.8.7
 2. rake-0.9.2.2
 3. All versions
> 2

You have requested to uninstall the gem:
        rake-0.9.2.2
addressable-2.2.6 depends on [rake (>= 0.7.3)]
...
If you remove this gems, one or more dependencies will not be met.
Continue with Uninstall? [Yn]  Y
Successfully uninstalled rake-0.9.2.2
INFO:  gem "0.9.2.2" is not installed

$ bundle install

In case if you use rvm. you can try following

rvm gem list

Try to execute:

gem list

You'll probably see a couple of version installed for rake. By the way, bundle exec is the right way of executing your code in the context of a Rails application. So, you can use an alias for typing less.