f a b u l o u s
9 aberration RHD bad, y'all should know this by now. The roper's ability scores are okay (22 strength is nice, 4 intelligence is abysmal, everything else is somewhat above average), 60 ft. tremorsense has its uses, and four 20 ft. reach 1d6 damage tentacles aren't the worst natural weapons to have, especially not with dexterity-damaging poison. Secondary paralysis is hardly relevant in most situations, sadly. Also +20 to hide in underground environments, because why not? 10 ft. land speed is a problem, though.
Color Spray is... nearly irrelevant as a SLA, especially on something that doesn't have the speed for optimal battlefield positioning.
Apart from the poison tentacles, the roper's main selling point is its Hypnotic Coloration. Everything that sees it might become fascinated, and if it does it'll start slowly walking towards the roper.
...except, y'know, fascination breaks as soon as anything remotely dangerous happens nearby. Considering this, I do not think the ability is going to be very useful. Add to this that the effect is non-friendly (unless, say, your entire party is blind) and prevents the roper from using its enormous hide bonus, and I think it can safely be written off.
Final verdict, -0 LA for a monster that has a somewhat interesting concept but will mostly just slow down the party and distract its teammates. At ECL 9 you may be able to create a reasonable melee build despite the crap RHD, but I can't say I'm very sure of that.