Baby in 98th percentile for weight!? How to speed things up?!

Marie • Mama to Finn born August 2016 & pregnant with baby number two, due October 2020. ♥️
37 + 3, had an ultrasound a few days ago and was told baby is in the 98th percentile for weight and 7.9lbs! I know they aren't entirely accurate but at 32 weeks we were told he was measuring in 80th percentile so we were expecting big but not THAT big. FTM and he's on track to being 9-10lbs if we make it to 40 weeks! I've only gained 27 lbs (162lbs) and haven't gained anything in 2 weeks and no diabetes. Anyone else expecting a big baby?!
Also, holy cow it's really really August!! I'm 4 cm, 80% effaced, and baby is at station 0. Has been for a week, so hoping he's coming soon before he gets any bigger! Any suggestions to speed things along/get water to break?! My midwife said raspberry leaf tea and castor oil won't do anything since I've been having contractions that have been dilating since 32 weeks! It's just the slowest longest labor ever. 😂 And it's getting old now!