Identify the order of the events and layers in this cross section image.
(1) is the oldest, (9) is the youngest.

We can use Steno's and Smith's principles to determine the relative age of rocks. The law of superposition states that the younger layers are found at the top and the older layers are found in the bottom. So using this, we can tell which layers were formed first. 

1 Layer H formed
2 Layer G formed
3 Layer F formed
4 Layer E formed
5 Layer D formed

All these layers are sedimentary rocks formed through weathering and erosion.  Sedimentary rocks are formed when layers of bits of other rocks and inorganic materials go on top of one another and are pressed into rocks due to pressure. 

According to the principles of cross-cutting relationship, which states that a fault or intrusion is younger than the rocks that it cuts through, we can say that fault X formed, shifting rocks H through E.

7 After layers H to E and the X fault formed, an intrusion A occurred (this is an igneous intrusion). It cut through the layers and the fault. The intrusion occurred before layers B and C as you can see that it does not cut through it. 

8 C layer formed, which would be sedimentary, through weathering and erosion again over the intrusion and the fault. Same goes with the next layer;

9 B layer. This is the youngest rock as it formed a layer over all the rocks, the fault and the intrusion. And as time passes, more layers will go over it and that would make it younger than this layer.