No not really. Speaking Creole is not mandatory in Seychelles at all. English is widely spoken in social and work life here. Little bit of French will benefit but that too is not really really required as the people here are too sweet to trouble you for your language.
Do not worry, you can communicate with people in Seychelles, locals or visitors ,in English or French. Of course, if you're interested in the local language Creole, you can learn some during staying in Seychelles.