Is it okay to plot a quadratic graph using only the intercepts as guidance? or should you plot many coordinates?i know its kind of an idiotic...

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.