Homebrew Updating 11.8.0 to 11.9.0

[Fadednova]

I have a homebrewed 3ds with 11.8.0 and I would like to know, how should I update it to 11.9.0 to use eshop?

 

[The Catboy]

Details are always important.
What do you mean by "homebrewed?" Do you mean that you are just running stock and launching homebrews through an entrypoint? Or do you mean that you've installed a CFW like Luma3DS?
If you are running Luma3DS, then always check to make sure you are running the latest version, you can check by booting the system holding "Select" and compare it to the latest version
https://github.com/AuroraWright/Luma3DS/releases
If you are running the latest version of Luma3DS, then update via the System Settings. If you aren't, update to the latest verison, then update the system through the System Settings.