Curseforge is safe, 9minecraft, pcminecraftmods and others are not good websites. Check here for those that aren't trustworthy that steal mods, can have malware in the files and so on: https://stopmodreposts.org/sites.html
Also Forge isn't supported on MultiMC currently due to how Forge is in 1.13+ so Fabric is the only option for 1.14 modding, Rift for 1.13 and Forge & Liteloader both work on 1.12.2 and prior. For reasons why Forge 1.13 isn't supported check here: https://multimc.org/posts/forge-114.html
If you need anything else related to 1.14 Forge/Fabric just let me know.