I doubt you will get it if you are now just at 8850.. Not sure how long it goes but normally, for the final reward, you can't miss any missions/quests. Some grace to not get max orb collects but you pretty much have to hit all the missions before they expire.
I just got the first egg on my alt account and am not going for the final reward because I doubt I can get it. Main account hasn't missed any missions (except play 10 games til round 3-6, never do those), orbs haven't been ideal, and I'm at 12500 xp and doubt even the main account will reach it.
Missions should reset again tomorrow morning though..
If you like the game, keep doing missions as they come out. It has a timer under them as to when they expire. When that timer is up, new ones come out. Sometimes there are more missions in a run, but if you have them all done, you have to wait til that timer was set to expire for new ones :)