My 9 month old male cavalier has developed an annoying habit/behaviour recently which is driving me potty!!

When he is out on a walk and meets another dog or playing off lead with a group of dogs, he is constantly jumping up in their
faces and pestering them and he is always trying to lick them underneath, this is with both male and female dogs.??

Has anyone else experienced this behaviour?

I have been advised the only way to stop this is to have his neutered but I don't want to put him through that if its
more a behaviour issue and can be sorted with training?

Help please......