1. Can you open a scene from Lumion 9 Pro in Lumion 9 (Standard)?

Yes, the Lumion 9 Pro Scene will look exactly the same in Lumion 9 (Standard) as in Lumion 9 Pro.

The only limitation is that you can't edit any of the Lumion 9 Pro Effects, Models, Sounds, Lights and Materials in Lumion 9 (Standard).

Lumion 9 (Standard) Scenes can also be opened in Lumion 9 Pro.

2. Can you render a Lumion 9 Pro scene in Lumion 9 (Standard)?

Yes, Movies and Photos that are rendered in Lumion 9 (Standard) will look the same as Movies and Photos rendered in Lumion 9 Pro.

That way Lumion 9 (Standard) can be used as a half-price render node for Lumion 9 Pro.

See also:

Lumion website: Comparison of Lumion 9 and Lumion 9 Pro

Lumion website: Lumion specifications

Knowledge Base: Is it possible to upgrade from Lumion to Lumion Pro?