Looking on the internet deeply has found these results:

9 years experience is the most popular phrase on the web.

9 year experience 1165,000 results on the web	9 years experience 11,610,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
He's 9 years old, plays the trumpet. Kalix L�jrom is produced by hand and requires a high level of expertise and many years experience. Special Agent Dammers has over 20 years experience in the area of paranormal psychology. But I am a police officer, with 25 years experience and an exemplary record. I have eight years experience selling electronics in Sanyo store in downtown Tokyo. I have 20 years experience in prison security. 23 years experience, and now here I am working for you. He has 25 years experience and training; you do not.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

9 year experience

1165,000 results on the web

9 years experience

11,610,000 results on the web

More popular!

He's 9 years old, plays the trumpet.
Kalix L�jrom is produced by hand and requires a high level of expertise and many years experience.
Special Agent Dammers has over 20 years experience in the area of paranormal psychology.
But I am a police officer, with 25 years experience and an exemplary record.
I have eight years experience selling electronics in Sanyo store in downtown Tokyo.
I have 20 years experience in prison security.
23 years experience, and now here I am working for you.
He has 25 years experience and training; you do not.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.