I have a 9 week old lab puppy! He throw up this morning and it was thick mucus no blood or anything and then in the after noon he had his lunch and then 2 hrs later he throw up again? I just wanted to know what to do or if anyone knows what could be the matter with him?

Take him to the Vet - it is impossible to diagnose over the Internet. It could be something; it could be nothing.

Get it checked out.

How many vaccines has he had yet? When did you get him?

Was the definitely mucus?
Or was it yellow/white foam?

Puppies can quite often vomit, just like babies, especially if they have eaten and then played...
Keep a very close eye on him and if he continues to vomit or had any other symptoms get him to the vet immediately.

Place a call to your vet,