Can I use vinyl planking on porch?

You can , but I don't think it would last, you know. Weather is brutal.

yes

Depending on whether your porch is roofed and screened will make a huge difference. Also, you need to consider how much heat and cold the floor will be subjected to. If you don't ask too much of the floor, I'd go for it.

Is it wood laminate? If so, it won't hold up under sun/moisture. If it's composite planking (plastic) then it should do great.

On the other hand, vinyl floors do not stand up well to heavy loads and can be damaged by sharp objects. Also, colors can fade with exposure to too much direct sunlight and floors can be damaged by extreme temperatures. For that reason, vinyl is not recommended for outdoor or indoor/outdoor uses.