How can u check ahead of time to see if hydrogen fuel available at this station?

Either use the mobile address or the desktop version at https://cafcp.org/stationmap

Most accurate is m.cafcp.org. don't rely on the apps. They are not reliable. Especially when these station companies are consolidating.

Use the SOSS website at m.cafcp.org

https://m.cafcp.org/ to check the local stations and what amount is available