Question: First of all I just started doing barre chords after learning ordinary non-barre chords. Problem is they don't sound so well, so my question is, will training with hand grippers help me achieve this? Because I've been applying equal pressure and they still sound a bit off, only a bit off.

Answer: 
It turns out that strength is not what is needed to improve your ability to finger barre chords, or any chords. It's mostly about precise placement and using the minimum amount of force to hold it down.

It's not necessarily that equal pressure is correct. You just need the right amount of pressure for each fret and string.
No, training with hand grippers won't help you execute barre chords. Firstly, time spent squeezing grippers is time that you could be using to actually practise barre chords. Secondly, the physical action is markedly different and not about finger placement and subtleties of pressure. But hey, you could end up with a really impressive handshake, and all the other musicians will ask you to carry their gear. It's early days; hang in there and your barre chords will improve.