Where can I buy some d size 9.5 inch carbon tubes at a decent price. I have been trying to buy them from apogee but it will not let me checkout.

Why when there's Ti and SS out there?

Carbon fibre is not great for sound suppressors.  A little bit of heat and it will get soft.  Attaching it to metal is a non-trivial problem.

I've made some 22 rimfire cans using CF tube and in the end, it was no lighter than aluminum tubing.

i'm quite sure the OP is talking about carbon steel

Or he could just go to the gym if he wants to lift weights.

I can only imagine how heavy and unweildy a carbon steel tubed can would be LOL!

Depends alloys like 4140 are much stronger than Ti which means you can run them thinner thus offsetting the weight penalty. You have to run finer pitch threads to get them thinner though which often is advised to run longer thread tennon's which adds the weight right back  But for a welded can I wouldn't be afraid to run .035-.045 4140 on a non full auto use can.

Carbon and stainless weigh w/in 1% of each other. Plenty of commercial cans are available in all SS designs (some include super alloys) and come in around and under a pound.

One of my form 1's is 100% 17-4 and is right at 16oz.

Take care to denote that heat treatment is critical for most martensitic alloys to achieve their high strength.  17-4 is one of the few which exceeds Ti in the annealed state.  Annealed 4140 has a tensile yield strength of only 60 KSI, lower than 7075-T6 aluminum, 1018 mild steel, 304 SS, 316ss, gr. 9 Ti, and less than half the strength of annealed 6/4 Ti.

Therein lies the appeal of titanium alloys and 17-4 stainless to many form 1 guys; the materials are very strong without any treatment, no need for carefully controlled processes as you would need to realize the potential of high carbon steels, nickel steels, chromoly, maraging steels or martensitic stainless grades