At 9 months old your pup is still a puppy and not potty trained. Most dogs aren't considered fully potty trained until after a year old because they simply aren't mature enough. Think of it like a toddler who is so interested in the thing they are doing that they forget they have to go. It sounds like she's not quite ready for the level of freedom you're providing for her, so scale that back a bit.
You may need to take her outside yourself, on leash, to ensure she goes potty. This isn't a forever thing, just until she gets the idea and can alert you/take herself outside. If you're having troubles with her going potty in places she shouldn't, she may need more supervision and direction. If you can't supervise, put her in the bathroom since that has worked. Make sure to praise and reward for a successful potty trip outside, and clean up accidents inside with an enzymatic cleaner like Nature's Miracle. It should also be noted that dogs don't generalize well, so that may be why it appears she understands she should use the doggy door during the day, but doesn't understand she should use it at night, too.
Honestly, I probably wouldn't trust her to be completely potty trained and able to take herself out through the doggy door until the 1 - 1.5 year mark. By then it seems the connection between the brain and their bladder is fully established, and they're mature enough to know when they have to go.
You may need to take her outside yourself, on leash, to ensure she goes potty. This isn't a forever thing, just until she gets the idea and can alert you/take herself outside. If you're having troubles with her going potty in places she shouldn't, she may need more supervision and direction. If you can't supervise, put her in the bathroom since that has worked. Make sure to praise and reward for a successful potty trip outside, and clean up accidents inside with an enzymatic cleaner like Nature's Miracle. It should also be noted that dogs don't generalize well, so that may be why it appears she understands she should use the doggy door during the day, but doesn't understand she should use it at night, too.
Honestly, I probably wouldn't trust her to be completely potty trained and able to take herself out through the doggy door until the 1 - 1.5 year mark. By then it seems the connection between the brain and their bladder is fully established, and they're mature enough to know when they have to go.
