Similiar:
Turn-based pausing (like you mentioned).
Several spells.
Many skills.
Train to expert/master/gm (mm9 is a little more fluid where people teach both expert/master). However the people are outside (not a static house), so sometimes it is hard to find a specific trainer.
Can hire NPCs that fight with you.

Differences:
No Flying.
Cannot select different class at the beginning. MM9 uses a unique class-tree system.
Getting around the world prior to town portal/beacon is slow... really slow.
MM9 uses tunneling. What I mean is that you cannot explore the world, you are forced to follow a strict path (a tunnel), unlike MM6-8.
No Obelisks?
Interface redone. "Z"-menu is somewhat different and imo, less useful. Spellbook is redone, a bit better. Skill views redone to the new class system. Spell learning redone. Skill learning redone (you can pick up books and learn them in the wilderness or a city store). Inventory is much better. Picking up treasure is a lot worse. Identifying treasure to see if you want it is non-existant. Monster corpses are bags. Bags disappear if they leave your view range outside.