There is an option to merge messages into the messneger app, you could do that and use the method I posted previously, although that is a bit rediculous just to be able to use gifs. It really shouldnt be this difficult.
Hey mate try this. Stumbled upon it by accident. I've got the s9+ as well.
When you're typing a message, press the little keyboard button down the bottom right hand corner, as shown in the screenshot. (1)
Select the Samsung keyboard neural beta (2)
Keyboard should look a little different now (3)
Can finally search gifs!!!! (4)
I came here to figure out why I couldn't search gifs either but I figured it out with the help here. I press the square smiley then this comes up- stickers AND gifs. And I can click on the search that appears, not in the message bar. Hope this helps.
That is a different keyboard. The "samsung keyboard neural beta" is not installed by default and is not in the Play store, however you can download the APK from various places. It has beta (new/test) features that get vetted before getting put in the real app, "samsung keyboard". This may be good news, because it appears samsung is working on an update that will fix this.