Hi Jean-Michel,
it is not quite the same but if you choose the PlotTheme-> "Classic" option that makes the plots look more similar to MMA9. They are not identical though.
Plot3D[Sin[0.3 (x^2 + y^2)], {x, -6, 6}, {y, -6, 6}, PlotPoints -> 50,PlotTheme -> "Classic"]
gives
as opposed to
in MMA9, where the colours are move vivid. There are a variety of PlotThemes that you might like.
Cheers,
Marco
