A question about reading and calculating thermal resistance of a voltage regulator from its datasheet

I have this voltage regulator from this supplier and the exact model name is given as: "LM317T/NOPB".

I plan to use this circuit to power a windwane's potentiometer which is around 10k:

As you see I want to set the excitation voltage for the vane pot to around 9 or 10V where the opamp will be supplied directly from a 12V switch mode power supply. For this purpose I will use an LM317 to obtain 9 or 10V for the vane excitation. So I will set LM317 for 9 or 10V DC. I will mount the vane in a box around 50m height which will stay there at least 3 months.

Since I will use a linear voltage regulator I decided to find out whether I need a heatsink.

I have encountered two challenges which I put here as questions:

1-) In the datasheet when I check the thermal resistances I cannot figure out which model I should use:

Mine is T0-220, but in the datasheet there is two types namely as KCT and KCS. But my model is "LM317T/NOPB". And on it it is written "LM317T +P". So should I use the thermal resistance for KCT or KCS?

2-) Here is how I calculate the ΔT:

ΔT = θJA * P

In my case:

P = V^2 / R = 10^2 / 10000 = 0.01W

But for junction to ambient temperature I used to use the following:

Junction to ambient = Junction to case + Case to Ambient

But in the datasheet there is no Case to Ambient but there is Junction to ambient. Does "junction to ambient" already include "case to ambient"? Should I in my case only use Junction to ambient? If so in my case ΔT becomes like 4°C, and I conclude I don't need heatsink. Do I calculate correct and does it matter the duration like three months when it comes to using heatsink?