Bicycle Mechanics - Front deraileur, braze-on vs clamp?

I want to upgrade my 9sp triple clamp-on FD to Ultegra (105 would be ok) but can't find a 9sp triple clamp-on. Everyone I've found online is 10sp and I don't want to change to 10sp. I did find a 105 9sp triple braze-on but I need a clamp-on. Can I just order a clamp and use a braze-on FD? Is there anything else I need to make it work right? Does using a braze-on type FD with a clamp change the chainline?
Thanks!

Braze-on FDs with clamp-on adapters work fine and don't change anything. I prefer that setup, so the FD is universal. The clamp-on adapter can stay with the frame, if desired.

It'll work just fine. The only trick is to be sure that you get a clamp diameter that matches your seat tube.

Wait, shouldn't a 10 speed FD and 9 speed FD be pretty much interchangeable?
A little less space for the chain, but you could always just get a narrower 10speed chain.
There is no problem with the shifters and no need to "change to" 10 speed.

I was under the impression that 9 & 10-speed FDs are pretty interchangable.

The 10-sp chain is narrower but the spacing between chainrings is the same (or at least real close), and that's what really matters.

Braze-on FDs with clamp-on adapters work fine and don't change anything. I prefer that setup, so the FD is universal. The clamp-on adapter can stay with the frame, if desired.
+1. The braze-on fd plus the clamp adapter cost slightly more than a clamp-on fd but, once you have the adapter, you can use it with any braze-on fd. Braze-on fds, by themselves, are cheaper than clamp-ons so any changes or upgrades cost less.

BTW, if your seat tube is 1-3/8" (35mm), PM me. I have an extra Shimano clamp adapter and it's yours for the asking.

Personally, I find the braze-on FD + clamp-adapter easier to adjust and fine-tune. There's a separate bolt for vertical versus rotation adjustment.

Personally, I find the braze-on FD + clamp-adapter easier to adjust and fine-tune. There's a separate bolt for vertical versus rotation adjustment.
Some are set up that way. The adapter has a vertical slot that allows fd height and rotational adjustment without moving the adapter's clamp.

Shimano adapters hold the fd in a fixed position so you have to set the height and rotation using the adapter just the way you would for a clamp-on fd. However, once you have the adapter oriented correctly, you can remove and replace the derailleur itself with no change in the fd's position. Since there is no reason to remove the adapter, it certainly simplifies removing and replacing the derailleur for cleaning.

Thanks for all the info. I think I could use a 10sp FD if I used a 10sp chain but I don't know if there would be a problem with a 10sp chain on a 9sp triple crankset? I figured the easiest/cheapest thing to do would be to buy a 9sp FD if I could still find one. So I think I will order the 9sp 105 FD and the clamp adapter.

HillRider I have a 31.8mm seat tube. Thanks for the offer.