WHUT. That's not true at all about 8w9s or 8w7. You're obviously putting personal bias on your experience. Let me show you the correct description:
8w7s are less inhibited and tend to be colorful characters. They tend to have more mercurial life patterns. They are more cocky and convey a "it's a priviledge for you to engage me" vibe. They intend for reality to contour itself around the way they go about their business. They expect the red sea to be parted for them. They are a double-gluttony subtype and are more likely to have the itch to gamble and be high-rollers. They are vulnerable to taking on too much risk and overextending themselves. They are more frenzied and cathartic and have more self-destructive tendencies. They tend to be iconoclasts who delight in turning things upside down instead of solidifying them.
8w7s believe the best defense is a good offense.
Their style of dominating is to preemptively attack you to keep you off balance. They delight in "checkmating" you as their seven wing makes them focus on where your options and possibilities are so they can cut them off. They have a greater focus on tactics and strategy. They are more "I reign supreme and will summon all my powers to blow you to smithereens".
8w9s tend to be more reserved and self-contained. They are more modest and friendly. They aren't as megalomanic as 8w7s. They are less likely to overestimate themselves. T
hey speak in simpler language and seem less "heady" than 8w7s with their more drawn out cadence. They don't understand the eight-winged-seven self-destructive behaviour. They are more grounded and unmovable but they can get aggressive in a hurry if provoked. They are natural defenders who focus on solidifying structures as opposed to tearing them down and starting anew.
8w9s believe the best defense is to be well-fortified.
They don't believe in preemptive aggression. They wait for the enemy to strike first and are natural counterpunchers. Their style of dominance is to endure whatever you throw at them and gradually steamroll you. They delight in pushing their weight against you and making you feel their physical presence. They are more "I am unbreakable and will steadily wear you down".
Source:
http://typewatchenneagram.blogspot.com/2011/06/typewatch-enneagram-type-descriptions.html