No you've done something wrong in the install. there should be parts 1,2,3 not 1,9,10.

Try unsubscribing from everything, restarting, then subscribe only to the latest DEI - parts 1,2,3.

Mod used to have a lot more parts as at that time there were heavy restrictions on mod file size so we had to split it like that.
Now its just 3 parts if you use workshop version OR 2 parts if you use manual install version which is superior due to having 2-3 times shorter load times.

Outdated mod message can be ignored as it does not work well ingame. If you have missing pictures, you dont have full mod install or you have conflict with other mod.

When I look at what I am subscribed to, its only 1+2+3, no other mods. I uninstalled the game, removed the game folder and the folder in team/steamapps/workshop/content/214950 where the folders for 1+9+10 were. Reinstalled the game, when I start the game it installs the missing mod files but it again installs file 1+9+10 and says that the files are old. Now the files in the explorer is as stated but the files in Steam that are checked are 1+2+3 but when I try to start it says the old files are called 1+9+10. The game starts fine but I have just played one turn. So is it possible that the files are called 1+2+3 in steam but are actually 1+9+10?

The files in the explorer are called
___divide_et_impera_010_part1.pack
___divide_et_impera_010_part9.pack
___divide_et_impera_010_part10.pack

They are 1+1,5+1,8 GB large

Any ideas?

Its fine, these are just names of old mod parts since Steam does not let you change file name as it would require whole new pack to be uploaded.