watts per gallon is pretty antiquated, kind of like the "1 inch per gallon" rule.
You can get 10W Daylight CFLs (
Amazon.com: GE 85393 10-Watt DayLight CFL Spiral Light Bulb, 2-Pack: Home Improvement) which will help a little. Also floating plants are wonderful for reducing the intensity seen below, and fish enjoy having the shade. Several people have been quite successful in a 10g using these. I myself have two 14W bulbs but am thinking of going down to the 10W.
However, for duration if you are getting algae problems I would reduce down to 8 hours a day and certainly get a timer, they are less than $10 and easy to find. Get one at a hardware or department store, cheaper than pet stores.
What you have won't go away though with changing lights, you'll just stop the spread of it. To get ride of it, you need to trim the plants. A small amount of algae isn't exactly bad though either, it removes nutrients the same as the plants themselves do. During weekly water changes use a sponge scrubber to clean your front glass and keep it clear, even if you don't see anything on it yet. Slow growing plants like Anubias and Java Fern are more susceptible to algae, they like to be shaded so again floating plants are key (several stem plants can be used floating, for example Water Sprite and Brazilian Pennywort). And of course, ensure your tank is not getting direct sunlight.
Back to the ick... using salt is not a good idea with plants. You can use some medications though, coppersafe is one option. Some plants may be affected, but overall should make it without issue. Take a look at this thread:
http://www.tropicalfishkeeping.com/aquarium-plants/ich-planted-tank-90561/
The entire tank will be infected with ick, including the plants. It can only be killed in the free floating stage, which is why raising the temp is helpful in speeding up the cycle and getting them free floating sooner so they can be killed. 84-86 shouldn't be a problem for the betta, the profile here for the Siamese Fighting Fish shows 84 as acceptable for them (but being at the extreme edge long term is not a good idea).
If you are already using a medication (which it sounds like you are) just keep it up per directions on the package and a few days after the spots disappear (to ensure ALL of them are dead, not just ones on the fish).
Also, just to make sure you have already, the carbon needs removed from your filter as it will suck up the medication. Plus you don't want carbon in a planted tank anyways (it can remove nutrients the plants need).
I would personally not recommend vacuuming the gravel. You can disturb the roots for substrate rooted plants and you remove nutrients needed by the plants. Many aquarists with heavily planted tanks never clean the substrate as the excess food and detritus breaking down provides nutrients and CO2 naturally for the plants.