Does a steeper graph mean a greater acceleration?

Yes.

Yes! But only for velocity vs. time graphs. is the slope of the line on a velocity time graph.

On a position vs. time graph the acceleration is represented by the curvature of the graphed function. Concave up regions of the graph (like a smile) correspond to time intervals with positive acceleration; concave down regions (like a frown) correspond to time intervals with negative acceleration.