EU9, has become a vital part of the European Union (EU). This cluster entered the EU in its third enlargement phase in 2004, bringing diversity and fresh perspectives into the grand unity.

The EU9 nations include Poland, Lithuania, Latvia, Hungary, Czech Republic, Slovakia, Slovenia, Estonia, and Malta. These nations have given significant inputs towards enhancing the goals of the European Union.

In this respect, understanding the role these nations plays in the EU is necessary for any study relating to international relations, politics, or European economics.

Since their induction, the states belonging to EU9 have given majestically towards shaping the European Union's policies. Their geographical location provides important strategic edges, rendering them a considerable part of the EU's defense and security strategies.

Additionally, these countries have significantly contributed to the European Union's economic strength. The EU9 nations' rapid economic development and eager integration into the European market has created heightened trade among other EU members.

The social contribution of the EU9 is also significant. These states bring profound historical backgrounds, individual cultural practices, and varied languages, therefore enhancing the variety of the here EU.

The inclusion of EU9 has also impacted the internal politics within the EU. With their presence, the power dynamics have changed, with new coalitions and alliances forming.

In conclusion, the roles played by the EU9 nations are significant. From economic influence to cultural richness, and from security strategies to political dynamics, EU9 has strengthened the European Union's framework. As such, an comprehensive understanding of the EU9 is essential to fully grasping the complexities of the European Union.