Consider the time it takes to get through passport control on arrival, (Unsure of wait time, varies greatly) and cab into the city 30 plus minutes at that time of night. I advise to arrive at the airport at least 3 hours ahead of time, plus cab ride to the airport minimum 30 minutes, probably more. At maximum you could be in Paris from 11 pm to 9:15 am, and the time is likely much less. Are you all sharing one room? Not sure how easy it is to find rooms with 2 double beds. Are all 4 going to shower? That is more time used up.
If you really want to see Paris, My suggestion is to pre-book a hotel near the Eiffel Tower, check in and decide if you have energy to walk to the tower that night; ensure you can have very late check in. Pre-arrange for a car service to meet you at the airport, your name on the sign kind of thing. Wake early, see the Tower and Seine, breakfast, checkout and cab to airport. Pre-arrange cab back to airport too. I agree with a previous poster, seeing the Eiffel Tower from the Trocadero right across the river is my favourite view.
The Eiffel Tower area is safe enough, there are pick pockets and girls wanting you to sign a protest form in order to pickpocket you. I walk in that area alone a lot.
In 2014, I had a cab pickup from the airport; it was a suggestion from the apartment I rented, [email protected], parisatshuttle.com, 55 Euro, 1 person and I used the same company to return to the airport, nice service. Last fall I used an online booking to get back to the airport which might have been Les Cars, a good service.
Do plan a return to Paris!