Key behaviours / activities to look out for this month are:
Possibility of a 'false rut'
General quietening down of roe deer behaviour, especially towards the end of the month for the bucks
Mothers and fawns regularly seen together
As you know, the roe deer have already rutted during the summer months, but occasionally, it is possible to see a brief resumption of territorial and aggressive behaviour at the start of October (or in late September).
This is called a 'false rut', and it's the younger bucks that are most likely to engage in this event.
You can see them starting to scent mark vegetation again, instigating chases with the does, engaging in tussles with similar sized bucks and performing Flehmen responses. (A Flehmen response is where a male will pull back the tissues surrounding his mouth, in order to maximise the intake of scent from the surrounding air.) In other words, behaving very similarly to how they did during the main rut in the summer. But when it comes to mating.... I have never seen roe deer mating in the autumn, or even seen a buck attempt to mount a willing doe.
At this stage of the year, the does and fawns will be quite settled in their daily routines, and you will be able to see them moving around their home range.
You will also notice that the deer's coat has now transitioned into a thicker, darker pelage, giving them a thick, winter blanket, which will provide protection through the inclement weather that lies ahead.