is fuel system treatment necessary on my 2009 Camry Hybrid?

Hello, fuel system treatments are not required by any manufacturer, but are a product of non original equipment manufacturer maintenance recommendations. Be wary of service folks who push additives like this. They may have a slight benefit and certainly cannot hurt anything, but I'm not sure they provide a massive improvement to the performance and longevity and economy of your vehicle. Some vehicles with direct injected fuel systems may experience modest improvements in combustion chamber cleaning, but it's modest. Your manufacturer maintenance schedule is the one you want to follow closely.