Are there vehicle booking to-fro airport? are they safe? we have 7 people.

Yes, you will find several car rental companies that can provide pick-up service.
You need to figure out which one is an official one. Avoid to get into the private car.
If you can find the official one, generally speaking, it's safe. Don't worry.
There are many types of cars for you to choose.

I once used eHi, and they are OK. This is their contact info in GZ: (020)3761-0138