The intercepts do not provide enough guidance to plot a quadratic graph. At the very least, you need the intercepts and the vertex. If you know the vertex, then you can draw a vertical line of symmetry and use the intercepts as guides. However, you should plot more coordinates if you can, preferrably in pairs with matching y-coordinates. This will show the symmetry of the parabola.
I require my students to plot the following coordinates:
* both intercepts
* the vertex
* 3 points on the left side of the line of symmetry and 3 cooresponding points on the right side of the line of symmetry.
I know many teachers who vary from me on the last requirement, but every teacher expects the intercepts and the vertex to be plotted.