All that @Jaxz says, and…
…don’t be shy to try on Osprey Kids packs either, might fit you and a bit cheaper.
And I must stress
…make sure you try on several packs with at least 9kg evenly loaded. I know people who prefer their nasty old K-Way over Gregory due to fit. I’ve also tried on ‘brilliant’ packs that ate into my body somewhere. Wear the pack in the store for a bit and if they have stairs climb them up and down. Also, not all sizes are made equal either despite a near so-called std method to measure volume. Best option is to maybe take your large gear to the shop and see how easily it packs. Or simulate the mission with similar in-store gear.
But certainly take yr time.
EDIT:
p.s. It might help if you indicated a budget, lots of people on this forum have been down the same pack buying tunnel in the last few years so that’s something that could facilitate advice
And…read these threads: