Is it possible to connect usb-c cable to dv9 for a console connection in iPad?

While USB-C to RS232 Serial Converters are available for Windows PC and other computers (the RS232 Serial Interface often presented as a DB9 or RJ45 console connection), none are known to be compatible with iPad.

Interface converters require appropriate device-driver software on the host device. iOS/iPadOS doesn't provide the facility to independently add device driver software to iPad, instead requiring Apps to provide the required device driver for a connected device.

Unless you are able to identify a specialist Terminal App for iPad that supports a specific Serial interface device, you'll not be able to achieve your aim.

As an alternative, consider using a proprietary WiFi/Bluetooth to Serial interface - and a appropriate App. Here is one possibility to explore:

https://www.get-console.com/shop/en/27-airconsole

What is a "DV9"? Do you mean DB9? If so, probably not, but if you'll tell us what console you're talking about and what you would like to achieve with this connection, perhaps someone can offer suggestions.

Regards.