A springer always on the go? sounds like you have a normal springer to me. i have had springers 2 at the moment and yes they are/have been full of energy my 9 year old being no different.

All my 3 have been different sizes so dont worry about his weight, a fat 10 month old springer and i would be worried, my youngest has been the skinniest she is 15 months now and is just begginning to fill out mine are fed burns which is known for keeping weight off but she is very small framed anyway. Dont worry he will fill out as he gets older the trouble with springers they are never still long enough for the fat to settleD and for me thats good.