You can find actual information about public traffic and The Nine Streets on www.bereikbaar.amsterdam.nl
Where are road works being carried out? What sort of work is it? How long will it take? What does this mean for the various forms of traffic? These pages offer you an overviews of road works being carried out on the most important through roads, as well as large-scale events both in and around Amsterdam. Which bus, tram or metro will get you to the Nine Streets shopping area? The GVB website will provide you with an answer, just look on gvb.nl.
Would you rather get there by car? You can park your car for only € 5.50 for a whole day in Amsterdam. This is possible at one of the P+R locations, just outside the centre. Your car is parked in a guarded car park and two public transport return tickets are included in the price.