Yes, you will get some nice views of the planets with that scope, it depends on your expectations though, dont think you'll get some hi-res like image similar to what you see on TV because you won't but if you're like me, you get a certain pleasure in seeing a planet with your own eyes, it's so much different than seeing it on a TV screen. Chances are, your eyepiece is a 25mm which won't give you much magnification, I use my 25mm as my view finder to center objects in the middle of my scope then I swap the 25mm out for a 9mm with a 3x Barlow lens. A 25mm eyepiece on an 800mm focal length will give you 32x magnification (800 x 25 = 32) add a 3x Barlow and you'll be at 96x zoom. If you get a 9mm eyepiece and a 2x barlow lens you'll be at the maximum magnification for your 90mm aperture at 177x zoom, at that level you'll get some pretty good views of Jupiter and Saturn and their moons.
This website explains how to work out the magnification of the eyepieces in your telescope. And here's a nice set of eyepieces. You could probably find the eyepieces separately on ebay if you dont want the full set.
Edit: also the Google sky map app is pretty damn useful
Okay, those look great. I was looking around, and a kit seems solid as well. What is your opinion on something like this? Will it cover all of the things I want to see?
Meade Instruments 607001 Series 4000 1.25-Inch Eyepiece and Filter Set (Black) https://www.amazon.com/dp/B00Z17ZD5O/ref=cm_sw_r_cp_apa_n6z4Bb140ZN0D