I want to use my Wi-Fi Printer with my MacBook and it works great when the Printer connects to the Wi-Fi Network created when I set up Internet sharing. What I want to know is, is there a way to set up the MacBook as a Wi-Fi Hotspot but without requiring an internet connection?
Yes, you just set up Internet Sharing the same as if you had an Internet connection on one of your non-Wi-Fi interfaces. You don't actually have to have a working Internet connection on the interface you use as the "From" (that's "From" as in, "Share your connection from:") interface. You just need to pick a non-Wi-Fi interface as the "From" interface so you can use your Wi-Fi interface as the "To" (that's "To" as in "To computers using:") interface.
Just like when you've used Internet sharing before, this will put your Wi-Fi interface into "Access Point" mode and start publishing whatever network name you tell it to publish. It'll also start up a DHCP server process to assign private IP addresses to any devices that join the Wi-Fi network it's creating.
The devices that join the Wi-Fi network won't be able to get to the Internet unless you bring up an Internet connection on whatever interface you used as your "From" interface.
What I figured out was that I could use Internet sharing to setup a Wi-Fi network if I connected the ethernet cable from my Macbook pro to a router (Apple AirPort Express in my case). This worked even if the router didn't have Internet access.
The reason why I did this is that the router had only 802.11 a/n Wi-Fi support, while the Internet sharing on my Macbook pro, mid 2015, is 802.11 ac. My tests showed a speed difference of ~250 Mbps vs. ~50 Mbps between a Macbook pro and an iPhone 6.