Final answer:
The code segment that can be inserted in the function is 'return time > 9'.
Step-by-step explanation:
In the blank, we can insert the code segment:
return time > 9
This code checks if the given time is greater than 9 and returns True if it is. Since the default value of is_weekend is False, we don't need to explicitly check it in the code. This code segment completes the wake_up function by returning True if the time is after 9 on any day, and False otherwise.