Does it apply to people who planned to start on Oct 1, 2025?

With the current system, you must apply in April if you succeed in the lottery, and then you can start in a few months in October, once per year.

Looks very uncomfortable for those who were about to relocate.

Looks like it:

a) Pursuant to sections 212(f) and 215(a) of the Immigration and Nationality Act (INA), 8 U.S.C. 1182(f) and 1185(a), the entry into the United States of aliens as nonimmigrants to perform services in a specialty occupation under section 101(a)(15)(H)(i)(b) of the INA, 8 U.S.C. 1101(a)(15)(H)(i)(b), is restricted, except for those aliens whose petitions are accompanied or supplemented by a payment of $100,000 — subject to the exceptions set forth in subsection (c) of this section. This restriction shall expire, absent extension, 12 months after the effective date of this proclamation, which shall be 12:01 a.m. eastern daylight time on September 21, 2025.