Traditionally you could not install plugins on WordPress.com. Recently it was announced that business plan customer could install plugins. So, yes if you have the business plan, you can use Caldera Forms on WordPress.com. If you have a different plan, you can not.
WordPress.com Business Now Supports Plugins and Third-Party Themes
Using Paid Caldera Forms Add-Ons With WordPress.com
It should be possible to use Caldera Forms add-ons not available through WordPress.org.
To install a plugin that is not availble on WordPress.org on WordPress.com, you must first install a simple plugin first, like Hello Dolly, using Calypso interface at wordpress.com/plugins. After doing so, the wp-admin plugin/theme upload will be available (before uploading the first one it’s still a classic WordPress.com site without that capabilities).