Wow! The lack of empathy, understanding & consideration for others on this thread is shocking!
NOT everyone has an iPhone or other phone with DND function SO many posters NOT GETTING THAT!
NOT everyone is a heavy sleeper some of us sleep very lightly and are easily woken and can't then get back to sleep
NOT everyone (quite a few ime now) has a landline
Some of us have sick/elderly relatives they need to be contactable for so can't have phones on silent, do not disturb type settings are also NOT suitable for everyone eg I have had calls from pay phones/hospital phones/switchboards where the number is withheld that would not have come through if only certain numbers could get through.
Just because you can send unimportant shite at any time doesn't mean you should
"Firstly who needs to send pics of their children playing st that time in the morning. And secondly she'd already told you once."
"I text whenever I want. It's not my problem if someone doesn't set their phone to silent/do not disturb when they don't want to be disturbed." Delightful attitude! 
"Could there be more to this OP? Do you frequently send videos etc of your dc?" Yea I'm wondering if op is more of a comms pest than she's making out too. Some people it's bloody constant!
"so I will speak about this with her later and I am seeing her next week, so we can chat properly" WHY?! To make her feel guilty for not living to your schedule? Just leave her alone before 9am except genuine energencies this is not hard! If I were her I'd be blocking you!!
"The chances of someone phoning you in the middle of the night in an emergency are very low aren't they really" not for everyone. Eg I have 3 people I could get calls about 2 of whom are very ill, regularly hospitalised. At one time it was 5 people.
Shocker - people's circumstances are different! And that's not allowing for the fact anybody I know could be trying to get hold of me in an emergency.
I also have a teen daughter who goes on sleepovers at various friends I don't have all her friends parents/grandparents/aunts/uncles/
Landline numbers especially as people do end up with new numbers at various points for various reasons. I'd want them able to contact me quickly & reliably if she took ill or had an accident. She also suffers from anxiety and has text me middle of night so as not to wake her friend so we can chat by text till she feels calmer.
Snapchat/whatsapp and similar notifications can be switched off on my phone, does anyone know if there are phones that can't do for these type of apps?
And faithinthesound (excellent user name gm fan here too) is spot on too! Your FRIEND asked you to not disturb her, therefore the polite, considerate thing to do is NOT to disturb her!
What's needed is an app that can differentiate between necessary/urgent calls/texts and random shite that nobody but the sender considers interesting 