EU9, is website now an essential part of the EU. The EU9 joined the EU in its third growth phase in 2004, injecting new ideas and cultural diversity into the EU society.

The members of EU9 include Poland, Lithuania, Latvia, Hungary, Czech Republic, Slovakia, Slovenia, Estonia, and Malta. These states have given meaningful inputs towards furthering the objectives of the European Union.

Therefore, grasping the role EU9 has in the EU is important for any study relating to European economics, politics, or international relations.

Since their induction, the EU9 nations have contributed substantially towards shaping the policies of the European Union. Their geographical location gives important strategic benefits, turning them a considerable part of the EU's defense and security strategies.

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

The social contribution of the EU9 is also significant. These countries introduce profound historical backgrounds, individual cultural practices, and varied languages, therefore enhancing the plurality of the EU.

The introduction of EU9 has also influenced the internal politics within the EU. With their participation, the power dynamics have changed, with new coalitions and alliances emerging.

In conclusion, the roles played by the EU9 countries are significant. From economic influence to cultural richness, and from security strategies to political dynamics, EU9 has robustly augmented the European Union's framework. As such, an thorough understanding of the EU9 is vital to fully grasping the details of the European Union.