Comprising of nine states, EU9 has become a vital element of the EU. The EU9 joined the EU in its third growth phase in 2004, implanting diversity and fresh perspectives into the grand unity.

The EU9 nations include Poland, Lithuania, Latvia, Hungary, Czech Republic, Slovakia, Slovenia, Estonia, and Malta. These countries each have given significant more info efforts towards furthering the objectives of the European Union.

Therefore, knowing the role these nations plays in the EU is required for any study relating to international relations, politics, or European economics.

Right from their admission, the EU9 countries have contributed substantially towards shaping the policies of the European Union. Their geographical location offers important strategic benefits, making them a vital part of the EU's defense and security strategies.

Additionally, these countries have significantly contributed to the European Union's economic strength. The EU9's rapid economic growth and willing integration into the European market has led to amplified trade with other EU countries.

The cultural contribution of the EU9 is also significant. These countries bring rich historical backgrounds, distinct cultural practices, and diverse languages, thereby enhancing the variety of the EU.

The inclusion of EU9 has also impacted the political dynamics within the EU. With their involvement, the power dynamics have altered, with new coalitions and alliances emerging.

In conclusion, the roles played by the EU9 members are significant. From economic influence to cultural richness, and from security strategies to political dynamics, EU9 has robustly augmented the European Union's structure. As such, an in-depth understanding of the EU9 is vital to fully grasping the complexities of the European Union.