I fully intend to employ the Hoover (despite my hated of it!) to make the corridor outside bedrooms a very noisy place in order to maintain a decent up time!
Unless you walk in on them, remove the quilt entirely and put it out of reach, pull up the blinds, and actually use the Hoover in their room, or even on their body....use the attachment to Hoover the fleas out of their hair....They will simply sleep through or purposely ignore you.
Son number one is up with the lark to row weekend mornings and has rowed 10km before most of us are awake, so if he wants a lie in during holidays, and he isn't rowing early, that is his choice, and he does enjoy a laze too. His youngest bruv is an early riser whatever time he goes to bed, middle bruv sleeps very heavily and quickly from 9pm most nights, so gets up about 7am, but he leads a frankly exhausting life.
I barely get past 9.30pm before I am dribbling from the corner of my mouth "watching" some trash on telly, g&t going flat on the coffee table, dh covertly risking a channel change before I wake up and declare, "i was watching that."
Son number one deffo seems to sleep more during big growth spurts too, he grew two inches over summer and was falling asleep on very short car journeys even.