No Mendoza or Iguazu???? That makes it tough

Just kidding, BA is a rather large and cosmopolitian city that offers a wide variety of activities. In 9 days you can certainly enjoy a nice selection of some of the great places to dine, take in the MALBA (Museum of Latin American Art) Palermo Soho, San Telmo Fair on Sunday, La Recoleta Cemetery, and on and on....but as for side trips you can take the ferry across the Rio de la Plata to Colonia, Urg. makes for a nice day trip or an overnight. Or the Tren de la Costa to visit Tigre and the delta area. And there are many estancias and smaller towns in the province of Buenos Aires that are very nice. San Antonio de Areco is wonderful, and has some wonderful estancias such as El Ombú de Areco for an overnight.
You might monitor the city tourism web site for events in the city during your stay
www.bue.gov.ar
suerte
SAM