No 'Itaewon Class' Episode 9 promo yet but worried fans should know Yi-seo unlikely to side with Chairman Jang
After having given up her college education to be by Sae-ro-yi's side and be a huge reason for his success, it is unlikely that Yi-seo would take Chairman Jang's side
'Itaewon Class' Episode 8 ended on a cliffhanger with Jang Dae-hee (Yoo Jae-myung) setting up a meeting with Park Sae-ro-yi's (Park Seo-joon) closest allies Cho Yi-seo (Park Da-mi). This is exactly why not having a promo for the upcoming episode might have fans worried. He did so in an attempt to poach Yi-seo to his side, just as he brought Soo-ah to Jang Corporation's side many years ago. He doesn't realize the key difference between the two of them though. While Soo-ah was a high school student who needed a sponsor, Yi-seo depends only on herself to achieve her ambitions.
Soo-ah might have been a bit in love with Sae-ro-yi in the past but she chose her path knowing the consequences. Similarly, Yi-seo is now in love with Sae-ro-yi and she has chosen her side too and she has made an informed decision as well. That became clear in episode 8 when Yi-seo -- who had until that point only thought about herself and Sae-ro-yi's success -- changed her tactics to align herself with Sae-ro-yi's ideals.
After having taken a step as huge as this, and having given up her college education to be by Sae-ro-yi's side and be a huge reason for his success, it is unlikely that Yi-seo would take Chairman Jang's side. However, this is not something Chairman Jang himself is aware of. All he is trying to do is weaken Sae-ro-yi by bringing Yi-seo on board his company. After having heard about how Sae-ro-yi's strength comes from people who believe in and who stand by his side; Jang is aggravated and he wants to somehow prove to this young man that in the world of business it is his methods that work. Yi-seo is just a tool in the grand scheme of things.
After having learned about Yi-seo in the last eight episodes, we are certain that her presence in Chairman Jang's office will serve Sae-ro-yi's purpose too. Yi-seo also knows the truth about how Chairman Jang and his elder son Jang Geun-won (Ahn Bo-hyun) ruined Sae-ro-yi's life. Yi-seo's love for Sae-ro-yi has also grown manifold in the days since she met him and saw different facets of his characteristics.
It started with when he refused to hold Yi-seo and her friend Geun-soo responsible for visiting his pub despite being underage. This resulted in his pub being shut but Geun-soo's brother Geun-won offers to help him. Yet, he refuses because he wants the law to be upheld. Then she sees how he responds when Soo-ah tells him that she was the one to push the cops on him. She sees how he reacts to one of his employees coming out as a trans person and finally, she learns of his path. All of this moved her beyond words and it is in these emotions that we trust.
As to what purpose her meeting with Chairman Jang will serve Sae-ro-yi; we have to watch that in the upcoming episodes. 'Itaewon Class' episodes can be streamed on Netflix.