How long does it take to get a work permit after receiving a Non-B visa in Thailand, and can I extend my stay with it?

The user is obtaining a single entry Non-B visa for teaching in Thailand and is inquiring about the timeline for their employer to secure a work permit and whether they can extend their stay at a local immigration office using that visa. Responses indicate that obtaining a work permit can take anywhere from 1 to 9 days depending on various factors, and achieving a visa extension seems contingent on having competent employer support without the necessity of being a shareholder.