Commerce Server 2009 uses cache for all its modules, including the profiles system.
It's uses cache for the obvious reasons : performance, data integrity and so on.
While working with the Commerce Server 2009 MCF or the old 2007 API, you should be safe.
Those APIs are responsible to update the cache via a dedicated cache handler.
There might be times when you would like to run scripts directly to the profiles database in the development, testing, staging or production environments.
If you do that, you should keep in mind that the cache should be updated / refreshed.
Configuring the profiles cache
While it cannot be configured via the web configuration file or any other configuration file or components,
You might want to configure the profiles service itself.
On more details on that you can find here
Refreshing the profiles cache
You might want to refresh manually the profiles cache to your Commerce Server business application or to your site.
You can do that using a special resource file (SiteCacheRefresh.axd). You can also control t he refresh cache using the applications' application pools related to them.
You can read here on exactly how to that.
For more information regarding the Commerce Server cache, go to this MSDN article.