Abstract: Beryllium-9 (⁹Be) is widely recognized as a key structural and functional material in nuclear engineering due to its excellent neutron reflection and neutron multiplication properties. Accurate nuclear data of ⁹Be are essential for reliable neutron transport calculations, reactor core design, and radiation shielding analysis, particularly in fusion reactors, accelerator-driven systems (ADS), and other advanced nuclear systems. However, discrepancies among different evaluated nuclear data libraries have been reported, especially in energy regions relevant to elastic scattering and (n, 2n) reactions. To address this, benchmark experimental data are urgently needed to validate and improve the existing datasets. In this work, the nuclear data of ⁹Be were systematically validated using the shielding integral experiment platform at the China Institute of Atomic Energy (CIAE). The experiments employed a well-characterized deuterium-deuterium (D-D) pulsed neutron source to investigate leakage neutron spectra from cylindrical ⁹Be samples with a diameter of 30 cm and thicknesses of 4.4, 8.8, and 13.2 cm. Measurements were performed at six detection angles: 34°, 45°, 63°, 117°, 135°, and 146°, using the time-of-flight (TOF) method to obtain energy-resolved neutron spectra with high precision. Parallel simulations were carried out using the MCNP code with four internationally recognized evaluated nuclear data libraries: CENDL-3.2, ENDF/B-Ⅷ.0, JENDL-5 and JEFF-3.3. Polyethylene samples were used as a standard for validating the experimental platform. In the n-p scattering peak region, the calculated-to-experimental (C/E) ratios of all four libraries are within 1.00±0.01, confirming the reliability and accuracy of the experimental measurements and simulation setup. Comparative analysis of the ⁹Be leakage spectra reveals important insights into the performance of the different data libraries. In the elastic scattering region, ENDF/B-Ⅷ.0 and JENDL-5 provide better agreement with the measured data, especially at large scattering angles. In the (n,2n) energy region, CENDL-3.2 shows relatively better consistency at small angles, while all libraries significantly underestimate the neutron yield at large angles, indicating systematic deficiencies in their (n,2n) cross-section evaluations for ⁹Be. This study provides comprehensive and high-fidelity benchmark data for ⁹Be under D-D neutron irradiation, offering valuable references for future nuclear data evaluations. The results support efforts to improve the accuracy of the CENDL library and enhance the predictive capabilities of simulation tools in shielding design, criticality safety and neutron transport applications.