UserBenchmark has confirmed that the EliteBook 835 G9 will ship with AMD Ryzen PRO 6000U processors, potentially up to the Ryzen 7 PRO 6850U. The EliteBook 835 G9 should be available in April alongside other EliteBook refreshes.
https://www.notebookcheck.net/HP-EliteBook-835-G9-UserBenchmark-listings-confirms-AMD-Ryzen-PRO-6000U-processors-for-upcoming-business-laptop.600870.0.html