Well I can only go by what my mother did because my kids aren't that old, but they are going to bed a bit late. My mother made us all go to bed by 7pm until we were in middle school. No questions asked, no arguments ever... or we got our bottoms swatted. My girls are 5 and 3 and we start bedtime at 7pm to 7:30...the are asleep no later than 8pm...my mom would disapprove. They are both up on their own by 7am or 7:30....I've read that kids need 10 to 12 hours a sleep a night until they are almost in their teens. Who knows for sure though...every person is different...I need eight, my hubby needs six to eight.
So anyway, try a little earlier bedtime.
Here are some things my mom would do. She turned on the light, gave us a kiss and said it was time to get up. We had five minutes...if we didn't get up...she pulled the covers off and stood over us with a glass of cold water...and she didn't bluff...we had 30 seconds to get up. Then she told us we had 15 minutes to get dressed or she went in and dressed us...typically in something she knew we hated to wear. Then we had to be finished brushing our teeth and combing our hair in 15 minutes and in the kitchen at a certain time. Each of us had a chore when we got there...one got the juice on the table, one got the napkins and silverware, the other helped with toast or fruit...whatever she was serving for breakfast.
My father was in the Air Force and he was gone for a year at a time sometimes. Mom didn't take any trash. She would praise us when we did a good job, but she wouldn't hesitate to set us straight if we gave her a hard time. That might mean a quick trip to the bathroom for a swat on the tail, or a promise that after school we wouldn't be able to watch tv for our hour or go outside at all that day. She made sure we understood she was the boss and there was no giving her a hard time....especially in the morning when things needed to get done.
If we argued then she punished us all to make sure she got the instigator or culprit. We soon learned to keep our mouths shut if we didn't have something nice to say. We might grumble under our breaths at each other but we made sure mom didn't hear it. She wouldn't tolerate the stress our bickering would create for her.
So get a timer and set it....give them time limits with consequences. It will be a pain for a few days but they will get the hint.
Kids become immune to yelling...I know I taught school for nine years...I learned that very quickly. You shouldn't yell unless absolutely necessary. Actions are what count. When one gives you a hard time enact a consequence...no arguments (they argue it gets worse).
Mom would often tell us that we did not live in a democracy it was a dictatorship and she was the boss...period.
I have to say we love and respect our mother deeply for it. She seemed like a tyrant sometimes...but though she was tough and laid down the law..she was also very generous with the praise and the hugs/kisses. I don't know that we have many friends that honor their mothers like me and brothers honor and respect ours.
Be tough, fair, loving, and firm. You are the boss and that is even more important in a military family.