In general, aim for 2 to 2.5 times the amount of beverage in your cup to the used coffee. If you use 9g of coffee in, aim for 18-23g out. The brew time stays the same. If you compare a single basket to a regular double basket you can see that it's narrower at the bottom, this is intended to restrict flow so you have approximately the same brew time using the same grind size but less coffee.
A brew time of 25-30 seconds is what you should aim for but it's not something you absolutely have to follow. It very well may be that your coffee tastes great at 36 or 23 seconds, it's just a ballpark.
From your question it seems that you're somewhat familiar with brewing espresso but still a beginner. There are a lot of good YouTube videos on this, made by people far more competent and eloquent than me. I think this video series on understanding each variable in brewing espresso is a good start if you're interested.