A compensated resistive divider sounds about right. Lets design it for you CRO 10:1 probe, 10 M +10 PF?. So ideally you want a 1.1 M, resistor to earth, then CRO point then 9 M to measurement point, the 9M would need a 1PF cap across. Thats 1 PF 1000VW,or you can get two pieces of insulated single core wire, solder one the the measuring end of the 9M, the other to the CRO point of the 9M. The free ends you then twist together, making sure the copper cores do not touch. View a voltage pulse shape with just the probe, make a note of it, then view it via your new 10:1 probe, if the rise time seems to have got longer, it means that your "1 PF" cap is too small and needs twisting up a bit more.
Frank