Not ALL features, at least not by default, but all the important ones yes (if you want to phrase it like that). Things like MSET are still not exploitable, but can be (at least for o3ds) if you install an older version of it. Also things like spiderhax (for things like code injection, like pokemon save dumping on 9.2) also won't work without downgrading browser version. But with A9LH those exploits it doesn't "fix" are unnecessary.
It also won't allow brahma payloads to work from HBL (decrypt9, emuNAND9, etc.) above 9.2 but those payloads can be run from A9LH at boot anyway.