1st off he said 8 or 9. But u are correct on your statment.
Secondly, bumpmapping is a dx5 feature i believe. (maybe its up to 6, but no higher) Maybe u mean "normal mapping" or "displacment mapping" or "pixel shaders" or something like that.
Upon further reading, certian types of bumpmapping are only enabled in dx8 on up. Some of the types of bumpmapping that the source engine uses are only enabled by these dx8 on up cards. Thus, i stand corrected by myself.
-Oh and it was dx6.0