Hi and welcome. What part of Florida do you live in? I am in North Central zone 9A. Some places in FL starting around the Tampa Orlando line and going South plant these out and they grow into full grown huge trees. Sometimes when you are driving on the freeway through there you can see them blooming in the right season.
I used to have one of these (its a Sheffelera) but I think I gave it away a long time ago. I can't help you with your questions, but in general, it may look leggy because it hasn't gotten enough light. Ones that I see growing out and about are upright because they are grown in very bright high light. If it's been in the same soil for 3.5 years, it IS most likely time for a repot into fresh soil.
How you repot is a touchy subject. I grow a lot of plants of many different genera and I was taught 30 years ago by mentor that when you repot you do not remove old soil, and you do not wash roots, and you do not trim roots unless its absolutely necessary. When I repot anything, I unpot it and gently shake it to remove just the soil that is loose. I leave what is around the rootball intact to minimize damage to the root system, the I place it in a container that is only one size higher than what its in (ex, if its in a gallon, I move it to a 2 gallon. If its in a 3 gallon, I step it up to a 5 gallon. If its in a little 2" pot, it gets a 4"pot etc.
