HONG KONG—A pro-democracy protester was sentenced Friday to nine years in prison in the closely-watched first case under Hong Kong’s national security law as the ruling Chinese Communist Party (CCP) tightens control over the territory. Tong Ying-kit, 24, was convicted of inciting secession and terrorism for driving his motorcycle into a group of police officers at a rally on July 1, 2020. He carried a flag bearing the banned slogan, “Liberate Hong Kong, revolution of our times.” The CCP imposed the security law on the former British colony last year following anti-government protests that erupted in mid-2019. The sentence was markedly longer than the three years requested by the prosecution. Tong’s defense lawyers appealed for no more than 10. He faced a possible maximum of life in prison. Critics accuse Beijing of violating the autonomy and Western-style civil liberties promised when Hong Kong returned to China in 1997 and hurting …