I am new to shooting video for my kids' soccer games. I've got a Canon DSLR and a tripod. I'm typically right near the sidelines unless there is bleacher seating which is definitely the minority. I'd love some recommendations on lenses that would do a good job.
I highly suggest you go to a Canon forum for your question. You didn't say which Canon camera you have and that too makes a difference. In days of yore (film days) it would not be atypical to see hobbyist photographers using something around an 80-200 range lens and usually the fastest lens they can buy (f/2.8 or f/4). Given that you are doing video, you would benefit from any vibration control, continual autofocus and ability to use larger memory cards (along with enough batteries to last the game and then some).
There are enough post process software packages out there to also realize if you are just slightly too far away you may opt with some "scenes" to give up a little quality for an in software crop.
If you have the time and patience along with a few bits in your pocket, you might consider renting a couple of lenses and see what works best in zoom range for you and if your camera will work well for fast action sports.
My camera does video but it absolutely would be terrible for shooting soccer games. Hopefully your Canon will serve you well on these video shoots. - Just practice for a bit before shooting a game that is important to you so you know the ins and outs of - pans, zooms, when to go wide and when to go tight (zoom in) etc. For sports, there is an craft involved and ability to anticipate.