After a couple months of watching SMW speedruns, I've decided to get into it myself but I have some questions.

A lot of runs are done on the Japanese SNES, is there any difference in using the USA SNES instead?

Im interested in trying the 11 Exit run, but it seems glitches like Orb or Cloud are mandatory. Can these glitches be done on the SNES Classic or Nintendo Switch?

Not really a SMW runner, so I can't say anything about the JP vs. USA versions. But I can say the Orb/Cloud glitches are not mandatory, they just save quite a bit of time. If you want to not use them, that's totally fine and accepted. In fact, you can filter the 11 Exit times by "Orb", "Cloud" or "Glitchless", in case you want to see a top run without the use of either the orb or the cloud.

Version differences: https://smwspeedruns.com/Version_Differences Mainly minor and not to worry about if you only have access to the US version.

Orb and Cloud are not mandatory at all in 11 Exit, if you go to the board and filter by Glitchless, you will see that there are a lot of runs. Almost everyone starts with 11 Exit Glitchless to learn SMW, I highly recommend it as well. Orb can be done on any version of the game (so yes to SNES Classic and Nintendo Switch), while Cloud can only reliably be done on an original SNES or SFC, on the original JP and US versions.