Here's the typical things to look at since your girls are rather slow reaching the laying point:
Are you sure you have only hens? I like the term 'Stealth Rooster' to describe the slow maturing or henny feathered roosters. Don't need one for the girls to lay. Even if you paid for sexing of your chicks, most hatchery or seller have a 90% accuracy rate, so it would be normal for you to have at least 3 roosters out of 30 hens, and this year has had lots of roosters, so it could/should be higher.
What type of layers are your breeds? The NHR should be laying now, my started at around 5 months and layed 6 out of 7 days, and I had a LF NHR, and I just got my first banties this year and I know silkies take awhile longer than LF production layers.
Have any of your girls combs and wattles turned red, and do they have a blush to their faces? It can be a gentle pink, as in my EEs or vivid red as in the Cuckoo Marans or Leghorn. Some breeds may not have combs or wattles on the females. Egg layers faces get 'red' when they are ready to lay.
Do your girls squat for you? I had no idea what that was, until I saw one of the red faced girls scrunch down and not argue with the roo over mating.
Have you checked your girls for mites or lice?
If their faces are red and they are squatting, have you set up the nesting boxes; darkened, that are just big enough for the hens, in your case, one slightly larger for the NHR, and small ones for the banties?
Have you tested your girls for egg eating?
Do you extend the light only in the morning, allowing them to go to bed at sundown?
If your girls range, have you searched for eggs? Do you provide oyster shell free choice?
I didn't recognize the egg song but I knew my girls would do labor coaching when another was in the nest, bok, bok, bok, BAWK, bok, breathe, breathe, breathe PUSH! breathe. Because of my hearing loss, they had been laying for weeks before I was working on the coop and saw that.
I hope the questions give you some different approach or insight. I don't want you to take insult even if they are basic questions.
And last but not least, your girls are 9 months old, so if 8-10 mos is correct, you won't be waiting much longer.
