I like both #5 and #9.
5- How a Mastermind Group Creates Synergy and Boosts Your Businesses Growth.
=> You might want to make “businesses” singular so your reader feels you’re writing to him personally: How a Mastermind Group Creates Synergy and Boosts Your Business Growth
9- 7 Captains of Industry Who Used Mastermind Groups to Grow Rich and Successful
=> I like this because the phrase “7 captains of industry” makes it specific and gives me the impression this is real-world, non-fluffy advice. The benefit “to grow rich” would probably be enough. Perhaps: How 7 Captains of Industry Used Mastermind Groups to Grow Rich
#4 is also good, but “transforming your business” could perhaps be stronger.
Enchant readers. Woo customers. Win business.