Is it possible to permanently disable group policy updates on Windows 7?

Don't do this. Your system administrator will know if you disable group policy completely. On top of that, many administrators use GPOs to deploy and manage software. When your computer doesn't report back as having the most recent version of the software, an Admin's head will tilt to the side slightly - and he's going to investigate the reason.

It is MUCH easier to override specific GPO objects you don't like, such as your home page being set in chrome (which could also be part of the way the software is deployed as much as a GPO object, as GPO generally only applies to M$ products). - Check this out - https://serverfault.com/questions/593937/can-i-override-domain-group-policy-with-local-group-policy-as-a-local-admin

If you create local GPO rules for the things you don't want mandated by your company - 1. The sysadmins are less likely to elevate your hackish tendancies to management, thus getting you fired, and 2. The sysadmins will probably tell you exactly how to do it. The home page being set static is usually both a security mandate, as well as a user support fix. I don't know how many times I've had people call because they can't find site X or Y, all of which are linked on our corporate portal home page... all because the user has changed their home page.

While it's important to keep the possible repercussions of your actions in mind, it is possible to disable group policy updates by deleting or (preferably) renaming the gpupdate.exe application in System32. To do this, you'll need to be a local administrator and take ownership of the file, then give yourself full control in the security tab.

If you have local admin privileges, maybe you could alter the ACL of the registry keys affected by the GPO to prevent them from being applied, as GPO's are basically remotely modified registry keys.

Meaning, if you were to deny the domain from having read/write access to these registry keys, that portion of the GPO cannot be applied.

Problem is you'll need to do it for every setting you want to preserve, one key for wallpaper, different key for home page, etc etc.