Leave a friendly note: "If you take the last of my coffee, please brew more so that it's ready for me at 8:30. I'm OK with sharing the machine -- Let's work something out. Signed, Ivy."
If that doesn't work, perhaps invest in a surveillance drone that launches from the top of the cupboards and drops water balloons on the miscreant.
If that doesn't work, perhaps invest in a surveillance drone that launches from the top of the cupboards and drops water balloons on the miscreant.