EU9, has become a significant part of the EU. This entity entered the EU in its 3rd enlargement phase in 2004, bringing diversity and fresh perspectives into the grand unity.

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

As such, knowing the role these nations plays in the European Union is necessary for any study relating to international relations, politics, or European economics.

Since their induction, the EU9 nations have given substantially towards shaping the European Union's policies. Their geographical location provides vital strategic advantages, turning them a vital part of the defense and security strategies of the EU.

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

The cultural contribution of the EU9 is also significant. These countries bring rich historical backgrounds, unique cultural practices, and varied languages, thereby enhancing the plurality of the EU.

The introduction of EU9 has also affected the political scene within the EU. With their participation, the power dynamics have changed, with new coalitions and alliances forming.

In conclusion, the parts played by the EU9 countries are considerable. From economic influence to cultural richness, and from security strategies to political dynamics, EU9 has strengthened the European Union's structure. As such, an in-depth understanding of the EU9 is essential to fully grasping the details of the European Union.