It is completely normal, don't worry.
There are tons of tips on how to stop this. First of all, to prevent the dog from getting overly excited because you came home, you should ignore him for the first few minutes. Once he calms down is when you pay attention to him.
Your situation is a little different because Toby has been holding his pee and really needs to go when you get home and so he leaks a little in anticipation of getting out.
So, I think you have two problems, and both are very common. Is he crated while you are gone? If so, maybe you should take the crate to the door and send him straight outside. If he is not crated, then maybe you can open the door and stand outside and get him outside to greet you.
This behavior should disappear as he grows older. There is information somewhere on this site, sorry I don't know where, that discusses how long a dog can hold his pee based on his age. So many hours for so many months old.
Hopefully someone else can direct you to that thread.
My Toby, who has just turned one year old had the same problem. But not only did he sprinkle the floor, he would get so excited that he would jump up on a chair or the couch and sprinkle a bit there too. I used the advice I had read here about ignoring him when I first came home, and it worked perfectly.
However, due to the very unusual circumstances at my house, he is still paper trained, so he can pee on the papers all day long. I live in the forest, so he cannot ever be let out on his own because my fenced yard is not safe enough. I would rather have pee soaked papers than to let him out and be a target for preditors.
Incredibly proud mom to Toby, my baby, and the amazing 8 year old Max who has found his forever home.