If I were to take the train there, I would only be allowed into the Tuna area after 9, by that time, will I still get to see people shipping tunas/cutting tunas etc?
some info from
http://www.tsukiji-market.or.jp/youkoso/24hour_e/24hours.htm
"In conjunction with the recent boom in the popularity of Tsukiji the number of tourists, including foreign visitors, paying a visit to the market is increasing. Experiencing the vibrant Tsukiji market presents a great opportunity for learning about the functions of the central wholesale market and the current perishables distribution system, but the both the wholesaling and reselling areas are busy places during the early morning hours.
Various problems have arisen in association with the increased number of tourists (including sanitation management problems such as temperature control issues caused by the entry and exit of large numbers of unauthorized persons, and problems with visitors impeding the auction and other trading activities), especially at the early morning auction held in the tuna wholesale area. For these reasons, tourists are currently not allowed to enter the tuna wholesaling areas.
To prevent any impediment to trading activities and to ensure food safety, these areas are closed to visitors and entering them in the early morning hours is not allowed.
Since the market is very busy with trucks, forklifts, and small vehicles moving about, guests are asked to be especially careful and vigilant when they visit.
Public guided-tours of Tsukiji Market are only available for groups of students (elementary school, junior and senior high school) and reservations may be made from 9:00 am to 3:00 pm. There are no public tours for other visitors or in other time periods. "