Lets say we make two circuits, one a simple circuit connected to a 9 V battery with say a 9 $\Omega$ resistor attached,and one another simple circuit connected to a 9 V battery with a 9 $\Omega$ resistor and a light in series. Now in both the circuits the total voltage drop will be 9 V. However, in the first circuit, there will be a 9 V drop over the 9 $\Omega$ resistor, and in the second circuit there will only be a less than 9 V drop over the same 9 $\Omega$ resistor (but still a 9 V drop between each battery terminal).
My question is, how can this same 9 $\Omega$ resistor produce two different voltage drops? I would imagine that since a simple resistor has a constant resistance, it would produce a constant voltage drop. Similarly, how can the total higher resistance of the series circuit produce the same voltage drop as a lower resistance circuit, such as the 9 $\Omega$ resistor wired in series with the battery? This is all assuming a constant voltage source such as a battery.
Maybe this is just a case of me overthinking and missing something simple. As a note I am just getting into electronics.