Filling form W-8 or W-9 for USA ESPP and Canada Brokerage

[rooks1rookie]

I am an Indian citizen. I was in the USA for the last 8 years (on H1-B) and just moved to Canada as a PR (same company) in May 2025.

1. I have an ESPP account in the USA that is still vesting , so the US brokerage firm has asked me to fill out a W-8 BEN form
2. I also have a personal brokerage account in the US with the same firm and I want to move in-kind to a Canadian firm. When I was trying to open an account, the Canadian firm is also asking me to fill a W-8 BEN form .

Given that I just moved, I am passing the Substantial residence alien test for this current year (spent almost all of the last 2 years in the USA, and till May in 2025) .

Should I not be filling out W-9 forms for this year, and then change it to W-8 BEN at the beginning of 2026 ?
Or do I fill the W-8 BEN now itself since my US residency is now terminated.

Any help is appreciated, thank you !