SRAM chain came with only half a powerlock
No, don't do that unless it's to limp the bike home. SRAM says not to and I've seen sufficient evidence it's for good reason.
The theoretical/manufacturer-stated reason not to is that the press fit is prone to not being as strong as intended once you've pushed the pin out and back in.
The pattern I've seen when people, myself included, do this is that it can seem to be fine but is in fact prone to breaking. When it happens it's usually during a shift under load, particularly in front. It needs to be in just the wrong spot, so you can see how it can give the illusion that it's fine.
Re-using an old one for a while would be fine, as would be using a 9-speed KMC Missinglink if you can find that locally.