Um, Book 6 says the 1990s should be TL9 (We aren't. Marc Miller isn't the only one disappointed.). From Book 4 our military tech seems more like TL8. Looking at Book 3, overall we are on the ragged edge of 6 and 7. Let us compromise to 7.
First, let us look at lasers
Optical Lasers. These are lasers using visible or near-to-visible light (IR through UV). An optical laser first shot down a target drone in 1972. Throughout the seventies bigger and better lasers shot down bigger and better targets, including jet drones, helicopters, and missiles. In the 1980s the SDI program stimulated development, but the hardware was never launched. Great improvements were made in focusing and fire control, as well as laser power. This can now be seen in two programs, the Air Forces Airborne Laser (ABL) and the Army's Theater High Energy Laser (THEL)
The ABL is a 3 MW(?) continuous chemical laser, It uses adaptive optics to compensate for atmospheric distortion, and can destroy ballistic missiles at up to1000 km. It should also be successful at shooting down anti-aircraft missiles or enemy planes at a hundred kilometers. A space-based version with a 4m mirror should have a range of 5-10,000 km.
Being a chemical laser, it burns fuel. A lot of fuel: it takes a 747 to carry it. The Air Force has a prototype, and wants ten more for real.
The Army's THEL is being co-developed with the Israelis (who call their version Nautilus). We want it to shoot down ballistic missiles (it turns out that the Patriot missile didn't really work), and the Israelis also want it to intercept katyushka artillery rockets (multiple 12-16cm targets). The Israelis expect to deploy Nautilus soon but the Army's version will be more mobile and will take a little longer.
Real world TL7 laser: 10,000 KM, 50 ton+ (but mostly fuel)
Traveller TL7 laser 250,000 km+, about 1 ton.
Some lasers can generate beams from an electrical input, this seems to be assumed in Traveller. The Free Electron Lasers vibrate a beam of electrons, and are tunable to a variety of frequencies. They are kinda bulky and inefficient, which means they generate much more waste heat than they send down range. Solid state lasers are basically a special type of light emitting diode. They are very efficient, but very, very weak. Something good may come of these in the future, but not before TL8.
The range of lasers depends on the frequency and the size of the mirror. If a 1.315^-6 m (infra-red) beam and a 4m mirror works out to a 10,000 Km range, then a 1m mirror (that would fit in a turret) and a 10^-8 m (short UV) wavelength should give you the 250,000+ km range of a turret laser. This seems plausible if you up the TL to 8.
X-ray lasers project very short wave radiation, so short it is difficult to focus. It could, theoretically be generated by Free electron Lasers, but there are a number of technical hurdles. I think this is the TL13 breakthrough. In the eighties it was proposed that a bundle of dense metal rods could be violently stimulated by a thermonuclear device. As the rods are destroyed they convert a small portion of the bombs energy into a powerful blast of collimated X-rays . Traveller 2300 used this technology to give missiles a very powerful warhead that would be effective from thousands of km.
Pulse lasers . . . well, in the '60s optically pumped lasers could reach higher energy in a pulse than a laser could continuously. I am not aware of any current line of research pursuing pulse lasers. It is an acceptable game artifact.
Verdict: 1TL off, no rules changes suggested.