Is the hotel near to the metro?
Also would we be able to have an early check in if we arrive at 9 am?
Yes you can take the light rail (which connects with metro) straight to the hotel. 8AM early check-in is normally offered for a fee to guarantee it, but your welcome to inquire and see what options are available. I was able to check in early a couple months back without extra fee. I did email them ahead and notify them I would be arriving early. In my case the hotel was fairly quiet and plenty of availability so it was no issue.
Yes near metro. Not sure about early check in
Get an answer from Sofitel Dubai Jumeirah Beach staff and past guests.