I want to mirror what's on my hudl 2 screen on to my tv. But only certain apps will work with chromecast. One suggestion was to root my tablet. Is the easy /safe to do?

I would check that the certain apps you want to mirror will work on a rooted device to begin with. Sky go for instance won't work properly on a rooted device.

Rooting is not going to help.

You can mirrorcast most things to chromecast assuming you are running kitkat or above. You have to set it up via the chromecast application.

^^ this. Very important.