We are pleased to announce the 9th workshop on breakdown science and high gradient accelerator technology, HG2025, will be held in Merida, Yucatan, Mexico from March 24-28, 2025. Clearly the identification and advancement of high gradient accelerator technologies for a linear collider have been the main goal since the inception of the High Gradient workshop series. Historically, the workshop has heavily concentrated on progress of X-band accelerator technologies, the area in which the most recent research results have been shared and discussed. The tight collaborations among the participants have pushed practical accelerator technologies to a level that has never been achieved before. Knowledge gained through the HG workshops in the past, like the current depth in understanding RF breakdown, the procedure of fabricating and conditioning high gradient accelerators, and the novel designs of high power rf components, etc., have benefits far beyond the X-band accelerator community. Besides the intensive focus on X-band high gradient accelerator technologies, the workshop has always made efforts to broaden the spectrum of technologies discussed and attract more talent in related fields. In recent years, the workshop has successfully recruited theorists in material science and experts in accelerator applications, whose participation has significantly enriched the program and generated mutual benefits. HG2025 will continue this journey. The workshop will share the latest advancements in, but not limited to, breakdown science, high efficiency high power RF sources, low breakdown rate high-gradient accelerators, low cost accelerator fabrication technologies, novel accelerator designs, accelerator applications to light source, medical, and industrial technologies etc. The format of HG2025 follows the format of preceding workshops, i.e. oral presentations and discussions. We look forward to seeing you in Mexico. Organizing Committee Members: Chunguang Jing(ANL/Euclid Techlabs), John Power(ANL), Xueying Lu(ANL/NIU), Alejandro Castilla(CERN/JLab), Karla Cantun(UADY), Enrique Camacho(UADY), Georfrey Maury Cuna(UGTO), Cristhian Valerio Lizarraga(UAS)