9 tails from my understanding is based from the power of the server and previous attendance so it only makes sense that 9 tails is extremely weak on new servers, wouldn't make much sense to put a 9 tails that you would have on an established server (one with 30M+ HP) as it simply would not get killed in the alloted time and most people would be bored of it taking 0 damage and being one shot constantly within the first 5-10 minutes. Yes it isn't optimal and is quite annoying as those who get in to do damage have a huge advantage for leveling in the early stages of the server however after about a week 9 tails will grow to a more respectable amount of health and you will be able to get in. Moral of the story unless you are next door to the servers have an insane connection and a god like pc just don't stress about it for the first week as you will only get frustrated more and more.