I have a Strange modular 9” that I want to use in a small tire setup. I’ll need to widen it about a foot per side. I assume I’ll need to fab some axle tubes than to in but just wanted to make sure there wasn’t already something available. I don’t see anything on the strange website and haven’t called them yet to ask. Any thoughts on the best way to go about it are appreciated. I don’t have a jig and I feel like I can do it without one.

Are you speaking of the 26/27" cast housing or a steel welded housing with a conventional round-ish rear welded cover?

Isn't the intent of the modular 9 housing is that you can change the "modular" axle ends/tube to achieve the width you want/need?
Id call and talk to the Strange tech people about what you are wanting to do.
As far as narrowing or widening a rear end housing with out a fixture is not a very good idea. I made my own fixture years ago, pretty easy if you have access to a lathe to make bearing bushings. Find a junk hydraulic ram with at east a 1" diameter ram for your alignment bar.