Weak nerve dog ?

Hi just wondering what peoples takes are on a dog what’s Jaw and tongue is quivering when got the ball and has just released it. Is this weak nerves? Would it make him a fear bitter, he is 9 months . Is it something what gets better through time? Also would all the pups in the litter be like this are can the bitch throw out a pup with weak nerves now and again. Please help.