Grip endurance training. Questions.

The single biggest obstacle to my progression onto harder climbs has been grip endurance. Been gym climbing for about 8 months, I'm only working up to 5.9s. I feel like my technique has improved a lot, but I always end up bailing due to grip fatique -- my forearms eventually just give out.

I don't think I'm quite up for hangboard training yet, and I don't want to hurt myself.

I started experimenting with "wussy hangboard training", which is just hanging from a pull up bar by my fingers in various positions. This seems to give me the same "pump" and exhaustion I get from climbing (which I can't do more than 1-2 times a week, tops).

My questions are:

1. Is this appropriate training? And if so, what sort of program should I use? Just copy a hangboard training program?
2. Is there something else I could be doing? Grip strengtheners, etc?

Edit: I appreciate all the advice so far. Most people seem to think that my technique may be the problem (e.g.: overgripping, lack of balance), and I'll accept that this is likely. Despite this, I'd still like to know if there is any benefit for additional grip strength training? Or should I just ignore it and climb 1-2 times a week?