Convert CRYPT to CRYPT9

The .crypt9 file extension is a file format used by WhatsApp Messenger to encrypt and store message history data. It is an updated version of the original .crypt file format and is used to improve security and privacy for users. Currently obsolete format because the new versions like .crypt10, .crypt12, .crypt14, etc. replaced it.

You can try using an app called Omni-Crypt that runs as a background service on an Android device and will monitor and convert WhatsApp .crypt5-12 files to .crypt legacy encryption.

To convert a crypt file to crypt9, you will need to follow these simple steps.

1. First, locate the crypt file on your device and rename it to end with .crypt9.
2. Next, download and install a tool called WhatsApp Omni-Crypt (formerly Tri-Crypt).
3. Once installed, open the tool and select the .crypt9 file you just renamed.
4. Click the "Convert" button and wait for the process to complete.
5. This will convert the crypt file to crypt9, which can now be easily imported into WhatsApp.

Always back up your message history before attempting conversions or changes to the database file. 

Simply put, it is impossible to convert CRYPT to CRYPT9 directly.
Thus, there is no so-called crypt to crypt9 converter or a free online .crypt to .crypt9 converter to be found.